style: Fixed lint errors, and black formatting

Author: abhinand-c

src/graphql/utilities/coerce_input_value.py

@@ -70,14 +70,18 @@ def coerce_input_value(
         if is_iterable(input_value):
             coerced_list: List[Any] = []
             append_item = coerced_list.append
-            is_nested_list = bool(is_list_type(item_type) and len(input_value) > 1)
+            is_nested_list = bool(
+                is_list_type(item_type) and len(tuple(input_value)) > 1
+            )
             for index, item_value in enumerate(input_value):
                 if is_nested_list and not is_iterable(item_value):
-                    # All input values should be iterable for multivalued nested list types
+                    # Input values should be iterable for multivalued nested list type
                     on_error(
                         path.as_list() if path else Path(path, index, None).as_list(),
                         item_value,
-                        GraphQLError(f"Expected type '{inspect(item_type)}' to be a list."),
+                        GraphQLError(
+                            f"Expected type '{inspect(item_type)}' to be a list."
+                        ),
                     )
                 append_item(
                     coerce_input_value(