diff --git a/.gitignore b/.gitignore
index 6709d3188..b85a2f09a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -138,3 +138,7 @@ dask-worker-space/
 # Test output
 tmp/
 .tmp_evaluation
+
+# private
+grep.py
+memo.txt
diff --git a/autoPyTorch/datasets/base_dataset.py b/autoPyTorch/datasets/base_dataset.py
index 912af8b63..f7a920efa 100644
--- a/autoPyTorch/datasets/base_dataset.py
+++ b/autoPyTorch/datasets/base_dataset.py
@@ -27,7 +27,7 @@
 
 
 def check_valid_data(data: Any) -> None:
-    if not any(hasattr(data, attr) for attr in ['__getitem__', '__len__']):
+    if not all(hasattr(data, attr) for attr in ['__getitem__', '__len__']):
         raise ValueError(
             'The specified Data for Dataset must have both __getitem__ and __len__ attribute.')