docs: def get_summary(self, key, start, end, tz=None):
          """Get a summary for the series from *start* to *end*.  The summary is
          a map containing keys *count*, *min*, *max*, *mean*, *sum*, and
          *stddev*.
  
          :param string key: the series key to use
          :param start: the start time for the data points
          :type start: string or Datetime
          :param end: the end time for the data points
          :type end: string or Datetime
          :param string tz: (optional) the timezone to place the data into
          :rtype: :class:`tempodb.response.Response` with a
                  :class:`tempodb.protocol.objects.SeriesSummary` data payload"""
  
          url = make_series_url(key)
          url = urlparse.urljoin(url + '/', 'summary')
  
          vstart = check_time_param(start)
          vend = check_time_param(end)
          params = {
              'start': vstart,
              'end': vend,
              'tz': tz
          }
          url_args = endpoint.make_url_args(params)
          url = '?'.join([url, url_args])
          resp = self.session.get(url)
          return resp