docs: def postings(self, quarter, stats_counter=None):
          """Yield job postings in common schema format
  
          Args:
              quarter (str) The quarter, in format '2015Q1'
              stats_counter (object, optional) A counter that can track both
                  input and output documents using a 'track' method.
          """
          logging.info('Finding postings for %s', quarter)
          for posting in self._iter_postings(quarter):
              transformed = self._transform(posting)
              transformed['id'] = '{}_{}'.format(
                  self.partner_id,
                  self._id(posting)
              )
              if stats_counter:
                  stats_counter.track(
                      input_document=posting,
                      output_document=transformed
                  )
              yield transformed