diff --git a/tdclient/api.py b/tdclient/api.py
index 0cc3ed7..9431980 100644
--- a/tdclient/api.py
+++ b/tdclient/api.py
@@ -92,7 +92,7 @@ def __init__(
         retry_post_requests=False,
         max_cumul_retry_delay=600,
         http_proxy=None,
-        **kwargs
+        **kwargs,
     ):
         headers = {} if headers is None else headers
         if apikey is not None:
@@ -493,7 +493,6 @@ def build_request(self, path=None, headers=None, endpoint=None):
         return (url, _headers)
 
     def send_request(self, method, url, fields=None, body=None, headers=None, **kwargs):
-
         if body is None:
             return self.http.request(
                 method, url, fields=fields, headers=headers, **kwargs
@@ -597,7 +596,7 @@ def _read_csv_file(
         encoding="utf-8",
         dtypes=None,
         converters=None,
-        **kwargs
+        **kwargs,
     ):
         if columns is None:
             reader = csv_dict_record_reader(file_like, encoding, dialect)
diff --git a/tdclient/bulk_import_api.py b/tdclient/bulk_import_api.py
index e3e6a69..07cb10b 100644
--- a/tdclient/bulk_import_api.py
+++ b/tdclient/bulk_import_api.py
@@ -184,7 +184,7 @@ def bulk_import_upload_file(self, name, part_name, format, file, **kwargs):
 
         The default behaviour is ``"guess"``, which makes a best-effort to decide
         the column datatype. See `file import parameters`_ for more details.
-        
+
         .. _`file import parameters`:
            https://tdclient.readthedocs.io/en/latest/file_import_parameters.html
         """
diff --git a/tdclient/bulk_import_model.py b/tdclient/bulk_import_model.py
index 633b3ea..afad72e 100644
--- a/tdclient/bulk_import_model.py
+++ b/tdclient/bulk_import_model.py
@@ -6,8 +6,7 @@
 
 
 class BulkImport(Model):
-    """Bulk-import session on Treasure Data Service
-    """
+    """Bulk-import session on Treasure Data Service"""
 
     STATUS_UPLOADING = "uploading"
     STATUS_PERFORMING = "performing"
@@ -38,79 +37,66 @@ def update(self):
 
     @property
     def name(self):
-        """A name of the bulk import session
-        """
+        """A name of the bulk import session"""
         return self._name
 
     @property
     def database(self):
-        """A database name in a string which the bulk import session is working on
-        """
+        """A database name in a string which the bulk import session is working on"""
         return self._database
 
     @property
     def table(self):
-        """A table name in a string which the bulk import session is working on
-        """
+        """A table name in a string which the bulk import session is working on"""
         return self._table
 
     @property
     def status(self):
-        """The status of the bulk import session in a string
-        """
+        """The status of the bulk import session in a string"""
         return self._status
 
     @property
     def job_id(self):
-        """Job ID
-        """
+        """Job ID"""
         return self._job_id
 
     @property
     def valid_records(self):
-        """The number of valid records.
-        """
+        """The number of valid records."""
         return self._valid_records
 
     @property
     def error_records(self):
-        """The number of error records.
-        """
+        """The number of error records."""
         return self._error_records
 
     @property
     def valid_parts(self):
-        """The number of valid parts.
-        """
+        """The number of valid parts."""
         return self._valid_parts
 
     @property
     def error_parts(self):
-        """The number of error parts.
-        """
+        """The number of error parts."""
         return self._error_parts
 
     @property
     def upload_frozen(self):
-        """The number of upload frozen.
-        """
+        """The number of upload frozen."""
         return self._upload_frozen
 
     def delete(self):
-        """Delete bulk import
-        """
+        """Delete bulk import"""
         return self._client.delete_bulk_import(self.name)
 
     def freeze(self):
-        """Freeze bulk import
-        """
+        """Freeze bulk import"""
         response = self._client.freeze_bulk_import(self.name)
         self.update()
         return response
 
     def unfreeze(self):
-        """Unfreeze bulk import
-        """
+        """Unfreeze bulk import"""
         response = self._client.unfreeze_bulk_import(self.name)
         self.update()
         return response
@@ -136,8 +122,7 @@ def perform(self, wait=False, wait_interval=5, wait_callback=None):
         return job
 
     def commit(self, wait=False, wait_interval=5, timeout=None):
-        """Commit bulk import
-        """
+        """Commit bulk import"""
         response = self._client.commit_bulk_import(self.name)
         if wait:
             started_at = time.time()
@@ -201,12 +186,16 @@ def upload_file(self, part_name, fmt, file_like, **kwargs):
 
         The default behaviour is ``"guess"``, which makes a best-effort to decide
         the column datatype. See `file import parameters`_ for more details.
-        
+
         .. _`file import parameters`:
            https://tdclient.readthedocs.io/en/latest/file_import_parameters.html
         """
         response = self._client.bulk_import_upload_file(
-            self.name, part_name, fmt, file_like, **kwargs,
+            self.name,
+            part_name,
+            fmt,
+            file_like,
+            **kwargs,
         )
         self.update()
         return response
diff --git a/tdclient/client.py b/tdclient/client.py
index 4c1e972..de4fc32 100644
--- a/tdclient/client.py
+++ b/tdclient/client.py
@@ -6,8 +6,7 @@
 
 
 class Client:
-    """API Client for Treasure Data Service
-    """
+    """API Client for Treasure Data Service"""
 
     def __init__(self, *args, **kwargs):
         self._api = api.API(*args, **kwargs)
@@ -79,7 +78,7 @@ def database(self, db_name):
              :class:`tdclient.models.Database`
         """
         databases = self.api.list_databases()
-        for (name, kwargs) in databases.items():
+        for name, kwargs in databases.items():
             if name == db_name:
                 return models.Database(self, name, **kwargs)
         raise api.NotFoundError("Database '%s' does not exist" % (db_name))
@@ -229,7 +228,7 @@ def query(
         priority=None,
         retry_limit=None,
         type="hive",
-        **kwargs
+        **kwargs,
     ):
         """Run a query on specified database table.
 
@@ -258,7 +257,7 @@ def query(
             result_url=result_url,
             priority=priority,
             retry_limit=retry_limit,
-            **kwargs
+            **kwargs,
         )
         return models.Job(self, job_id, type, q)
 
@@ -927,8 +926,7 @@ def remove_apikey(self, name, apikey):
         return self.api.remove_apikey(name, apikey)
 
     def close(self):
-        """Close opened API connections.
-        """
+        """Close opened API connections."""
         return self._api.close()
 
 
diff --git a/tdclient/connection.py b/tdclient/connection.py
index 52aabd3..6f9f97f 100644
--- a/tdclient/connection.py
+++ b/tdclient/connection.py
@@ -13,7 +13,7 @@ def __init__(
         retry_limit=None,
         wait_interval=None,
         wait_callback=None,
-        **kwargs
+        **kwargs,
     ):
         cursor_kwargs = dict()
         if type is not None:
diff --git a/tdclient/database_model.py b/tdclient/database_model.py
index fb59813..c80c028 100644
--- a/tdclient/database_model.py
+++ b/tdclient/database_model.py
@@ -4,8 +4,7 @@
 
 
 class Database(Model):
-    """Database on Treasure Data Service
-    """
+    """Database on Treasure Data Service"""
 
     PERMISSIONS = ["administrator", "full_access", "import_only", "query_only"]
     PERMISSION_LIST_TABLES = ["administrator", "full_access"]
@@ -50,7 +49,7 @@ def name(self):
         str: a name of the database
         """
         return self._db_name
-    
+
     @property
     def id(self):
         """
diff --git a/tdclient/job_api.py b/tdclient/job_api.py
index 60b163b..bff39d4 100644
--- a/tdclient/job_api.py
+++ b/tdclient/job_api.py
@@ -160,7 +160,7 @@ def show_job(self, job_id):
             return job
 
     def job_status(self, job_id):
-        """"Show job status
+        """ "Show job status
         Args:
             job_id (str): job ID
 
@@ -208,7 +208,7 @@ def job_result_format(self, job_id, format, header=False):
             job_id (int): Job ID
             format (str): Output format of the job result information.
                 "json" or "msgpack"
-            header (boolean): Includes Header or not. 
+            header (boolean): Includes Header or not.
                 False or True
 
         Returns:
@@ -224,7 +224,7 @@ def job_result_format_each(self, job_id, format, header=False):
 
         Args:
             job_id (int): job ID
-            format (str): Output format of the job result information. 
+            format (str): Output format of the job result information.
                 "json" or "msgpack"
             header (bool): Include Header info or not
                 "True" or "False"
@@ -241,8 +241,12 @@ def job_result_format_each(self, job_id, format, header=False):
             format = "json"
 
         with self.get(
-            create_url("/v3/job/result/{job_id}?format={format}&header={header}",
-                       job_id=job_id, format=format, header=header)
+            create_url(
+                "/v3/job/result/{job_id}?format={format}&header={header}",
+                job_id=job_id,
+                format=format,
+                header=header,
+            )
         ) as res:
             code = res.status
             if code != 200:
@@ -282,7 +286,7 @@ def query(
         result_url=None,
         priority=None,
         retry_limit=None,
-        **kwargs
+        **kwargs,
     ):
         """Create a job for given query.
 
diff --git a/tdclient/job_model.py b/tdclient/job_model.py
index 1348368..9dafed5 100644
--- a/tdclient/job_model.py
+++ b/tdclient/job_model.py
@@ -7,8 +7,7 @@
 
 
 class Schema:
-    """Schema of a database table on Treasure Data Service
-    """
+    """Schema of a database table on Treasure Data Service"""
 
     class Field:
         def __init__(self, name, type):
@@ -48,8 +47,7 @@ def add_field(self, name, type):
 
 
 class Job(Model):
-    """Job on Treasure Data Service
-    """
+    """Job on Treasure Data Service"""
 
     STATUS_QUEUED = "queued"
     STATUS_BOOTING = "booting"
@@ -92,8 +90,7 @@ def _feed(self, data=None):
         self._result_export_target_job_id = data.get("result_export_target_job_id")
 
     def update(self):
-        """Update all fields of the job
-        """
+        """Update all fields of the job"""
         data = self._client.api.show_job(self._job_id)
         self._feed(data)
 
@@ -105,57 +102,48 @@ def _update_status(self):
         self.update()
 
     def _update_progress(self):
-        """Update `_status` field of the job if it's not finished
-        """
+        """Update `_status` field of the job if it's not finished"""
         if self._status not in self.FINISHED_STATUS:
             self._status = self._client.job_status(self._job_id)
 
     @property
     def id(self):
-        """a string represents the identifier of the job
-        """
+        """a string represents the identifier of the job"""
         return self._job_id
 
     @property
     def job_id(self):
-        """a string represents the identifier of the job
-        """
+        """a string represents the identifier of the job"""
         return self._job_id
 
     @property
     def type(self):
-        """a string represents the engine type of the job (e.g. "hive", "presto", etc.)
-        """
+        """a string represents the engine type of the job (e.g. "hive", "presto", etc.)"""
         return self._type
 
     @property
     def result_size(self):
-        """the length of job result
-        """
+        """the length of job result"""
         return self._result_size
 
     @property
     def num_records(self):
-        """the number of records of job result
-        """
+        """the number of records of job result"""
         return self._num_records
 
     @property
     def result_url(self):
-        """a string of URL of the result on Treasure Data Service
-        """
+        """a string of URL of the result on Treasure Data Service"""
         return self._result_url
 
     @property
     def result_schema(self):
-        """an array of array represents the type of result columns (Hive specific) (e.g. [["_c1", "string"], ["_c2", "bigint"]])
-        """
+        """an array of array represents the type of result columns (Hive specific) (e.g. [["_c1", "string"], ["_c2", "bigint"]])"""
         return self._hive_result_schema
 
     @property
     def priority(self):
-        """a string represents the priority of the job (e.g. "NORMAL", "HIGH", etc.)
-        """
+        """a string represents the priority of the job (e.g. "NORMAL", "HIGH", etc.)"""
         if self._priority in self.JOB_PRIORITY:
             return self.JOB_PRIORITY[self._priority]
         else:
@@ -164,44 +152,37 @@ def priority(self):
 
     @property
     def retry_limit(self):
-        """a number for automatic retry count
-        """
+        """a number for automatic retry count"""
         return self._retry_limit
 
     @property
     def org_name(self):
-        """organization name
-        """
+        """organization name"""
         return self._org_name
 
     @property
     def user_name(self):
-        """executing user name
-        """
+        """executing user name"""
         return self._user_name
 
     @property
     def database(self):
-        """a string represents the name of a database that job is running on
-        """
+        """a string represents the name of a database that job is running on"""
         return self._database
 
     @property
     def linked_result_export_job_id(self):
-        """Linked result export job ID from query job
-        """
+        """Linked result export job ID from query job"""
         return self._linked_result_export_job_id
 
     @property
     def result_export_target_job_id(self):
-        """Associated query job ID from result export job ID
-        """
+        """Associated query job ID from result export job ID"""
         return self._result_export_target_job_id
 
     @property
     def debug(self):
-        """a :class:`dict` of debug output (e.g. "cmdout", "stderr")
-        """
+        """a :class:`dict` of debug output (e.g. "cmdout", "stderr")"""
         return self._debug
 
     def wait(self, timeout=None, wait_interval=5, wait_callback=None):
@@ -235,8 +216,7 @@ def kill(self):
 
     @property
     def query(self):
-        """a string represents the query string of the job
-        """
+        """a string represents the query string of the job"""
         return self._query
 
     def status(self):
@@ -250,8 +230,7 @@ def status(self):
 
     @property
     def url(self):
-        """a string of URL of the job on Treasure Data Service
-        """
+        """a string of URL of the job on Treasure Data Service"""
         return self._url
 
     def result(self):
diff --git a/tdclient/result_api.py b/tdclient/result_api.py
index 1e2e332..c9c08df 100644
--- a/tdclient/result_api.py
+++ b/tdclient/result_api.py
@@ -22,7 +22,8 @@ def list_result(self):
                 self.raise_error("List result table failed", res, body)
             js = self.checked_json(body, ["results"])
             return [
-                (m["name"], m["url"], None, m["id"], m["user_id"]) for m in js["results"]
+                (m["name"], m["url"], None, m["id"], m["user_id"])
+                for m in js["results"]
             ]  # same as database
 
     def create_result(self, name, url, params=None):
diff --git a/tdclient/result_model.py b/tdclient/result_model.py
index b5801f6..3938f24 100644
--- a/tdclient/result_model.py
+++ b/tdclient/result_model.py
@@ -4,8 +4,7 @@
 
 
 class Result(Model):
-    """Result on Treasure Data Service
-    """
+    """Result on Treasure Data Service"""
 
     def __init__(self, client, name, url, org_name, id, user_id):
         super(Result, self).__init__(client)
@@ -17,30 +16,25 @@ def __init__(self, client, name, url, org_name, id, user_id):
 
     @property
     def name(self):
-        """str: a name for a authentication
-        """
+        """str: a name for a authentication"""
         return self._name
 
     @property
     def url(self):
-        """str: a result output URL
-        """
+        """str: a result output URL"""
         return self._url
 
     @property
     def org_name(self):
-        """str: organization name
-        """
+        """str: organization name"""
         return self._org_name
 
     @property
     def id(self):
-        """int: result id
-        """
+        """int: result id"""
         return self._id
 
     @property
     def user_id(self):
-        """int: result's owner id
-        """
+        """int: result's owner id"""
         return self._user_id
diff --git a/tdclient/schedule_model.py b/tdclient/schedule_model.py
index 9b09c88..f5f0e00 100644
--- a/tdclient/schedule_model.py
+++ b/tdclient/schedule_model.py
@@ -5,8 +5,7 @@
 
 
 class ScheduledJob(Job):
-    """Scheduled job on Treasure Data Service
-    """
+    """Scheduled job on Treasure Data Service"""
 
     def __init__(self, client, scheduled_at, job_id, type, query, **kwargs):
         super(ScheduledJob, self).__init__(client, job_id, type, query, **kwargs)
@@ -14,14 +13,12 @@ def __init__(self, client, scheduled_at, job_id, type, query, **kwargs):
 
     @property
     def scheduled_at(self):
-        """a :class:`datetime.datetime` represents the schedule of next invocation of the job
-        """
+        """a :class:`datetime.datetime` represents the schedule of next invocation of the job"""
         return self._scheduled_at
 
 
 class Schedule(Model):
-    """Schedule on Treasure Data Service
-    """
+    """Schedule on Treasure Data Service"""
 
     def __init__(self, client, *args, **kwargs):
         super(Schedule, self).__init__(client)
@@ -55,8 +52,7 @@ def __init__(self, client, *args, **kwargs):
 
     @property
     def name(self):
-        """The name of a scheduled job
-        """
+        """The name of a scheduled job"""
         return self._name
 
     @property
@@ -70,38 +66,32 @@ def cron(self):
 
     @property
     def query(self):
-        """The query string of a scheduled job
-        """
+        """The query string of a scheduled job"""
         return self._query
 
     @property
     def database(self):
-        """The target database of a scheduled job
-        """
+        """The target database of a scheduled job"""
         return self._database
 
     @property
     def result_url(self):
-        """The result output configuration in URL form of a scheduled job
-        """
+        """The result output configuration in URL form of a scheduled job"""
         return self._result
 
     @property
     def timezone(self):
-        """The time zone of a scheduled job
-        """
+        """The time zone of a scheduled job"""
         return self._timezone
 
     @property
     def delay(self):
-        """A delay ensures all buffered events are imported before running the query.
-        """
+        """A delay ensures all buffered events are imported before running the query."""
         return self._delay
 
     @property
     def priority(self):
-        """The priority of a scheduled job
-        """
+        """The priority of a scheduled job"""
         if self._priority in Job.JOB_PRIORITY:
             return Job.JOB_PRIORITY[self._priority]
         else:
@@ -109,8 +99,7 @@ def priority(self):
 
     @property
     def retry_limit(self):
-        """Automatic retry count.
-        """
+        """Automatic retry count."""
         return self._retry_limit
 
     @property
@@ -136,32 +125,27 @@ def created_at(self):
 
     @property
     def type(self):
-        """Query type. {"presto", "hive"}.
-        """
+        """Query type. {"presto", "hive"}."""
         return self._type
 
     @property
     def user_name(self):
-        """User name of a scheduled job
-        """
+        """User name of a scheduled job"""
         return self._user_name
 
     @property
     def id(self):
-        """int: id of the query
-        """
+        """int: id of the query"""
         return self._id
 
     @property
     def executing_user_id(self):
-        """int: executor's id of the query
-        """
+        """int: executor's id of the query"""
         return self._executing_user_id
 
     @property
     def description(self):
-        """str: description of the query
-        """
+        """str: description of the query"""
         return self._description
 
     def run(self, time, num=None):
diff --git a/tdclient/table_model.py b/tdclient/table_model.py
index 1a5c1ae..eb7ca9c 100644
--- a/tdclient/table_model.py
+++ b/tdclient/table_model.py
@@ -4,8 +4,7 @@
 
 
 class Table(Model):
-    """Database table on Treasure Data Service
-    """
+    """Database table on Treasure Data Service"""
 
     def __init__(self, *args, **kwargs):
         super(Table, self).__init__(args[0])
@@ -36,20 +35,17 @@ def __init__(self, *args, **kwargs):
 
     @property
     def type(self):
-        """a string represents the type of the table
-        """
+        """a string represents the type of the table"""
         return self._type
 
     @property
     def db_name(self):
-        """a string represents the name of the database
-        """
+        """a string represents the name of the database"""
         return self._db_name
 
     @property
     def table_name(self):
-        """a string represents the name of the table
-        """
+        """a string represents the name of the table"""
         return self._table_name
 
     @property
@@ -61,14 +57,12 @@ def schema(self):
 
     @property
     def count(self):
-        """int: total number of the table
-        """
+        """int: total number of the table"""
         return self._count
 
     @property
     def estimated_storage_size(self):
-        """estimated storage size
-        """
+        """estimated storage size"""
         return self._estimated_storage_size
 
     @property
@@ -87,14 +81,12 @@ def primary_key_type(self):
 
     @property
     def database_name(self):
-        """a string represents the name of the database
-        """
+        """a string represents the name of the database"""
         return self._db_name
 
     @property
     def name(self):
-        """a string represents the name of the table
-        """
+        """a string represents the name of the table"""
         return self._table_name
 
     @property
@@ -113,20 +105,17 @@ def updated_at(self):
 
     @property
     def last_import(self):
-        """:class:`datetime.datetime`
-        """
+        """:class:`datetime.datetime`"""
         return self._last_import
 
     @property
     def last_log_timestamp(self):
-        """:class:`datetime.datetime`
-        """
+        """:class:`datetime.datetime`"""
         return self._last_log_timestamp
 
     @property
     def expire_days(self):
-        """an int represents the days until expiration
-        """
+        """an int represents the days until expiration"""
         return self._expire_days
 
     @property
@@ -140,25 +129,21 @@ def permission(self):
 
     @property
     def identifier(self):
-        """a string identifier of the table
-        """
+        """a string identifier of the table"""
         return "%s.%s" % (self._db_name, self._table_name)
-    
+
     @property
     def user_id(self):
-        """int: owner's id of the table
-        """
+        """int: owner's id of the table"""
         return self._user_id
 
     @property
     def description(self):
-        """str: description of the table
-        """
+        """str: description of the table"""
         return self._description
 
     def delete(self):
-        """a string represents the type of deleted table
-        """
+        """a string represents the type of deleted table"""
         return self._client.delete_table(self._db_name, self._table_name)
 
     def tail(self, count, to=None, _from=None):
@@ -252,8 +237,7 @@ def export_data(self, storage_type, **kwargs):
 
     @property
     def estimated_storage_size_string(self):
-        """a string represents estimated size of the table in human-readable format
-        """
+        """a string represents estimated size of the table in human-readable format"""
         if self._estimated_storage_size <= 1024 * 1024:
             return "0.0 GB"
         elif self._estimated_storage_size <= 60 * 1024 * 1024:
diff --git a/tdclient/test/conftest.py b/tdclient/test/conftest.py
index e30032c..d6f72c0 100644
--- a/tdclient/test/conftest.py
+++ b/tdclient/test/conftest.py
@@ -1,10 +1,13 @@
 import pytest
 
 try:
-    from urllib3.contrib.pyopenssl import inject_into_urllib3, extract_from_urllib3
+    from urllib3.contrib.pyopenssl import (
+        extract_from_urllib3,
+        inject_into_urllib3,
+    )
 except ImportError:
-    inject_into_urllib3 = lambda: None
-    extract_from_urllib3 = lambda: None
+    inject_into_urllib3 = lambda: None  # noqa: E731
+    extract_from_urllib3 = lambda: None  # noqa: E731
 
 
 @pytest.fixture(autouse=True)
diff --git a/tdclient/test/cursor_test.py b/tdclient/test/cursor_test.py
index e5cd33e..f2c61e0 100644
--- a/tdclient/test/cursor_test.py
+++ b/tdclient/test/cursor_test.py
@@ -161,7 +161,7 @@ def test_fetchone():
     assert td.fetchone() == ["foo", 1]
     assert td.fetchone() == ["bar", 1]
     assert td.fetchone() == ["baz", 2]
-    assert td.fetchone() == None
+    assert td.fetchone() is None
 
 
 def test_fetchmany():
diff --git a/tdclient/test/database_model_test.py b/tdclient/test/database_model_test.py
index a077376..5651c71 100644
--- a/tdclient/test/database_model_test.py
+++ b/tdclient/test/database_model_test.py
@@ -26,7 +26,7 @@ def test_database():
         permission="administrator",
         id=123,
         user_id=1,
-        description="database description"
+        description="database description",
     )
     assert database.org_name == "org_name"
     assert database.permission == "administrator"
diff --git a/tdclient/test/dtypes_and_converters_test.py b/tdclient/test/dtypes_and_converters_test.py
index eba8dd2..3a80d7c 100644
--- a/tdclient/test/dtypes_and_converters_test.py
+++ b/tdclient/test/dtypes_and_converters_test.py
@@ -1,20 +1,15 @@
 #!/usr/bin/env python
 
-"""Tests for the dtypes and converters arguments to CSV import.
-"""
-
-import pytest
+"""Tests for the dtypes and converters arguments to CSV import."""
 
 from io import BytesIO
 from unittest import mock
 
-from tdclient import api, Client
-from tdclient.util import read_csv_records
-
-from tdclient.test.test_helper import gunzipb
-from tdclient.test.test_helper import make_response
-from tdclient.test.test_helper import msgunpackb
+import pytest
 
+from tdclient import Client, api
+from tdclient.test.test_helper import gunzipb, make_response, msgunpackb
+from tdclient.util import read_csv_records
 
 DEFAULT_DATA = [
     {
@@ -39,15 +34,13 @@
 
 
 def sample_reader(data=DEFAULT_DATA):
-    """A very simple emulation of the actual CSV readers.
-    """
+    """A very simple emulation of the actual CSV readers."""
     for item in data:
         yield item
 
 
 def test_basic_read_csv_records():
-    """The base test of read_csv_records - no customisation.
-    """
+    """The base test of read_csv_records - no customisation."""
     reader = sample_reader()
 
     result = list(read_csv_records(reader))
@@ -128,7 +121,12 @@ def test_dtypes_change_parsing():
 
     result = list(
         read_csv_records(
-            reader, dtypes={"col1": "str", "col2": "float", "col6": "str",}
+            reader,
+            dtypes={
+                "col1": "str",
+                "col2": "float",
+                "col6": "str",
+            },
         )
     )
 
@@ -158,7 +156,14 @@ def test_converters_change_parsing():
     reader = sample_reader()
 
     result = list(
-        read_csv_records(reader, converters={"col1": str, "col2": float, "col6": str,})
+        read_csv_records(
+            reader,
+            converters={
+                "col1": str,
+                "col2": float,
+                "col6": str,
+            },
+        )
     )
 
     assert result == [
@@ -188,7 +193,14 @@ def test_dtypes_plus_converters_change_parsing():
 
     result = list(
         read_csv_records(
-            reader, dtypes={"col1": "str", "col6": "str",}, converters={"col2": float,}
+            reader,
+            dtypes={
+                "col1": "str",
+                "col6": "str",
+            },
+            converters={
+                "col2": float,
+            },
         )
     )
 
@@ -226,7 +238,11 @@ def test_dtypes_overridden_by_converters():
                 "col2": "int",  # overridden by converters
                 "col6": "str",
             },
-            converters={"time": int, "col2": float, "col5": str,},
+            converters={
+                "time": int,
+                "col2": float,
+                "col5": str,
+            },
         )
     )
 
diff --git a/tdclient/test/schedule_model_test.py b/tdclient/test/schedule_model_test.py
index 6345817..15a5732 100644
--- a/tdclient/test/schedule_model_test.py
+++ b/tdclient/test/schedule_model_test.py
@@ -41,7 +41,7 @@ def test_schedule():
         user_name="user_name",
         id=123,
         executing_user_id=1,
-        description="query description 1"
+        description="query description 1",
     )
     assert schedule.name == "name"
     assert schedule.cron == "cron"
diff --git a/tdclient/test/table_model_test.py b/tdclient/test/table_model_test.py
index df0850e..dd91c65 100644
--- a/tdclient/test/table_model_test.py
+++ b/tdclient/test/table_model_test.py
@@ -28,7 +28,7 @@ def test_table():
         primary_key="primary_key",
         primary_key_type="primary_key_type",
         user_id=1,
-        description='table description'
+        description="table description",
     )
     assert table.type == "type"
     assert table.db_name == "db_name"
diff --git a/tdclient/user_model.py b/tdclient/user_model.py
index cbfcb33..aee7556 100644
--- a/tdclient/user_model.py
+++ b/tdclient/user_model.py
@@ -4,8 +4,7 @@
 
 
 class User(Model):
-    """User on Treasure Data Service
-    """
+    """User on Treasure Data Service"""
 
     def __init__(self, client, name, org_name, role_names, email, **kwargs):
         super(User, self).__init__(client)
diff --git a/tdclient/util.py b/tdclient/util.py
index 800b7a1..f3f6d69 100644
--- a/tdclient/util.py
+++ b/tdclient/util.py
@@ -23,7 +23,7 @@ def create_url(tmpl, **values):
 
 def validate_record(record):
     """Check that `record` contains a key called "time".
-    
+
     Args:
         record (dict): a dictionary representing a data record, where the
         keys name the "columns".
@@ -52,7 +52,7 @@ def guess_csv_value(s):
     3. If it is "false" or "true" (case insensitive), then as a boolean
     4. If it is "" or "none" or "null" (case insensitive), then as None
     5. As the string itself, unaltered
-    
+
     Args:
         s (str): a string value, assumed to have been read from a CSV file.
     Returns:
@@ -86,7 +86,7 @@ def guess_csv_value(s):
 
 def merge_dtypes_and_converters(dtypes=None, converters=None):
     """Generate a merged dictionary from those given.
-    
+
     Args:
         dtypes (optional dict): A dictionary mapping column name to "dtype"
           (datatype), where "dtype" may be any of the strings 'bool', 'float',
@@ -94,7 +94,7 @@ def merge_dtypes_and_converters(dtypes=None, converters=None):
         converters (optional dict): A dictionary mapping column name to a
           callable. The callable should take a string as its single argument,
           and return the result of parsing that string.
-    
+
     Internally, the `dtypes` dictionary is converted to a temporary dictionary
     of the same form as `converters` - that is, mapping column names to
     callables. The "data type" string values in `dtypes` are converted to the
@@ -136,7 +136,7 @@ def parse_csv_value(k, s, converters=None):
         k (str): The name of the column that the value belongs to.
         s (str): The value as read from the CSV input.
         converters (optional dict): A dictionary mapping column name to callable.
-    
+
     If `converters` is given, and there is a key matching `k` in `converters`,
     then ``converters[k](s)`` will be called to work out the return value.
     Otherwise, `tdclient.util.guess_csv_value`_ will be called with `s` as its
@@ -169,9 +169,9 @@ def parse_csv_value(k, s, converters=None):
 
 def csv_dict_record_reader(file_like, encoding, dialect):
     """Yield records from a CSV input using csv.DictReader.
-    
+
     This is a reader suitable for use by `tdclient.util.read_csv_records`_.
-    
+
     It is used to read CSV data when the column names are read from the first
     row in the CSV data.
 
@@ -194,9 +194,9 @@ def csv_dict_record_reader(file_like, encoding, dialect):
 
 def csv_text_record_reader(file_like, encoding, dialect, columns):
     """Yield records from a CSV input using csv.reader and explicit column names.
-    
+
     This is a reader suitable for use by `tdclient.util.read_csv_records`_.
-    
+
     It is used to read CSV data when the column names are supplied as an
     explicit `columns` parameter.
 
@@ -218,9 +218,7 @@ def csv_text_record_reader(file_like, encoding, dialect, columns):
 
 
 def read_csv_records(csv_reader, dtypes=None, converters=None, **kwargs):
-    """Read records using csv_reader and yield the results.
-
-    """
+    """Read records using csv_reader and yield the results."""
     our_converters = merge_dtypes_and_converters(dtypes, converters)
 
     for row in csv_reader:
@@ -269,7 +267,7 @@ def normalized_msgpack(value):
 
     If `value` is a dictionary, then all the dictionary keys and values are
     (recursively) normalized.
-    
+
     If `value` is an integer, and outside the range ``-(1 << 63)`` to
     ``(1 << 64)``, then it is converted to a string.
 
@@ -295,8 +293,8 @@ def normalized_msgpack(value):
 
 
 def get_or_else(hashmap, key, default_value=None):
-    """ Get value or default value
-    
+    """Get value or default value
+
     It differs from the standard dict ``get`` method in its behaviour when
     `key` is present but has a value that is an empty string or a string of
     only spaces.
@@ -305,7 +303,7 @@ def get_or_else(hashmap, key, default_value=None):
         hashmap (dict): target
         key (Any): key
         default_value (Any): default value
-    
+
     Example:
 
         >>> get_or_else({'k': 'nonspace'}, 'k', 'default')
@@ -332,7 +330,7 @@ def parse_date(s):
     """Parse date from str to datetime
 
     TODO: parse datetime using an optional format string
-    
+
     For now, this does not use a format string since API may return date in ambiguous format :(
 
     Args: