code: def delete(self, *, page_size=DEFAULT_BATCH_SIZE, **options):
          
          from .model import delete_multi
  
          deleted = 0
          options = QueryOptions(self).replace(keys_only=True)
          for page in self.paginate(page_size=page_size, **options):
              keys = list(page)
              deleted += len(keys)
              delete_multi(keys)
  
          return deleted
docs: Deletes all the entities that match this query.
  
          Note:
            Since Datasotre doesn't provide a native way to delete
            entities by query, this method paginates through all the
            entities' keys and issues a single delete_multi call per
            page.
  
          Parameters:
            \**options(QueryOptions, optional)
  
          Returns:
            int: The number of deleted entities.