code: def _parent_info(self):
          
          parent_doc = self.parent
          if parent_doc is None:
              parent_path = _helpers.DOCUMENT_PATH_DELIMITER.join(
                  (self._client._database_string, "documents")
              )
          else:
              parent_path = parent_doc._document_path
  
          expected_prefix = _helpers.DOCUMENT_PATH_DELIMITER.join((parent_path, self.id))
          return parent_path, expected_prefix
docs: Get fully-qualified parent path and prefix for this collection.
  
          Returns:
              Tuple[str, str]: Pair of
  
              * the fully-qualified (with database and project) path to the
                parent of this collection (will either be the database path
                or a document path).
              * the prefix to a document in this collection.