code: def iter(self, headers_only=False, page_size=None):
          
          if self._end_time is None:
              raise ValueError("Query time interval not specified.")
  
          params = self._build_query_params(headers_only, page_size)
          for ts in self._client.list_time_series(**params):
              yield ts
docs: Yield all time series objects selected by the query.
  
          The generator returned iterates over
          :class:`~google.cloud.monitoring_v3.types.TimeSeries` objects
          containing points ordered from oldest to newest.
  
          Note that the :class:`Query` object itself is an iterable, such that
          the following are equivalent::
  
              for timeseries in query:
                  ...
  
              for timeseries in query.iter():
                  ...
  
          :type headers_only: bool
          :param headers_only:
               Whether to omit the point data from the time series objects.
  
          :type page_size: int
          :param page_size:
              (Optional) The maximum number of points in each page of results
              from this request. Non-positive values are ignored. Defaults
              to a sensible value set by the API.
  
          :raises: :exc:`ValueError` if the query time interval has not been
              specified.