message: Remove walrus operator for Python 3.7 compatiblity
diff: @@ -74,8 +74,10 @@ class PandasDataLoader(DataLoader):
  return inspect(self._db_engine).default_schema_name
  def _take_data_types(self, table: Table) -> Optional[Dict[str, str]]:
  - if metadata_table := table.table_metadata:
  - if types := metadata_table.types:
  + metadata_table = table.table_metadata
  + if metadata_table:
  + types = metadata_table.types
  + if types:
  return types
  return None
  