with open(file.path, 'r', encoding='utf8') as query_file:
                 filed_query: QueryData = json_load(query_file)
             assert isinstance(filed_query['results'], list)
-            assert type(filed_query['text']) is QueryText
-            assert type(filed_query['retrieved_at']) is DatetimeStr
+            assert isinstance(filed_query['text'], str)
+            assert isinstance(filed_query['retrieved_at'], str)
             id_ = QueryId(splitext(basename(file.path))[0])
             results_list = filed_query['results']
-            query_text = filed_query['text']
-            retrieved_at = filed_query['retrieved_at']
+            query_text = QueryText(filed_query['text'])
+            retrieved_at = DatetimeStr(filed_query['retrieved_at'])
             queries_data += [(id_, results_list, query_text, retrieved_at)]
         return queries_data