[stable-6] Avoid direct type comparisons (#7087)

Avoid direct type comparisons (#7085)

Avoid direct type comparisons.

(cherry picked from commit a8809401ee)

tests/unit/mock/loader.py

@@ -17,7 +17,7 @@ class DictDataLoader(DataLoader):
 
     def __init__(self, file_mapping=None):
         file_mapping = {} if file_mapping is None else file_mapping
-        assert type(file_mapping) == dict
+        assert isinstance(file_mapping, dict)
 
         super(DictDataLoader, self).__init__()