code: def single_value(self, key, ts=None, direction=None):
          
  
          url = make_series_url(key)
          url = urlparse.urljoin(url + '/', 'single')
  
          if ts is not None:
              vts = check_time_param(ts)
          else:
              vts = None
  
          params = {
              'ts': vts,
              'direction': direction
          }
  
          url_args = endpoint.make_url_args(params)
          url = '?'.join([url, url_args])
          resp = self.session.get(url)
          return resp
docs: Return a single value for a series.  You can supply a timestamp
          as the ts argument, otherwise the search defaults to the current
          time.
  
          The direction argument can be one of "exact", "before", "after", or
          "nearest".
  
          :param string key: the key for the series to use
          :param ts: (optional) the time to begin searching from
          :type ts: ISO8601 string or Datetime object
          :param string direction: criterion for the search
          :rtype: :class:`tempodb.response.Response` with a
                  :class:`tempodb.protocol.objects.SingleValue` object as the
                  data payload