new_contents: class BaseQuery:
      def __init__(self, **kwargs):
          raise NotImplementedError
  
      def __str__(self):
          if hasattr(self, "query_text"):
              return self.query_text
          raise NotImplementedError(
              "attribute self.query_text must be implemented "
              f"in class {self.__class__.__name__}"
          )
  
subject: Add BaseQuery