Use more pythonic list comprehensions in some places

Co-authored-by: Juan Miguel Carceller <[email protected]>

python/podio/frame.py

@@ -50,7 +50,7 @@ def _determine_cpp_type(idx_and_type):
 
 def _get_cpp_types(type_str):
   """Get all possible c++ types from the passed py_type string."""
-  types = list(filter(lambda t: type_str in t, SUPPORTED_PARAMETER_TYPES))
+  types = [t for t in SUPPORTED_PARAMETER_TYPES if type_str in t]
   if not types:
     raise ValueError(f'{type_str} cannot be mapped to a valid parameter type')
 
@@ -61,7 +61,7 @@ def _get_cpp_vector_types(type_str):
   """Get the possible std::vector<cpp_type> from the passed py_type string."""
   # Gather a list of all types that match the type_str (c++ or python)
   types = _get_cpp_types(type_str)
-  return [f'std::vector<{t}>' for t in map(lambda x: x[0], types)]
+  return [f'std::vector<{t[0]}>' for t in types]
 
 
 def _is_collection_base(thing):
@@ -243,7 +243,7 @@ def put_parameter(self, key, value, as_type=None):
 
       self._frame.putParameter[par_type](key, value)
     else:
-      if as_type is not None:
+      if as_type:
         cpp_types = _get_cpp_types(as_type)
         if len(cpp_types) == 0:
           raise ValueError(f"Cannot put a parameter of type {as_type} into a Frame")