Merge pull request #2100 from Yancey1989/fix2060

Bugfix: checkout input_type failed

python/paddle/trainer/PyDataProvider2.py

@@ -270,7 +270,7 @@ class CheckWrapper(object):
             assert isinstance(each, collections.Sequence)
             for d in each:
                 assert isinstance(d, float)
-            assert len(each, input_type.dim)
+            assert len(each) == input_type.dim
         elif input_type.type == DataType.Index:
             assert isinstance(each, int)
             assert each < input_type.dim