code: def _build_report(self):
          
          self.metrics = {}
          queries = {'visits': PiwikQueryReportEventMetricVisits(**self.params),
                     'unique_visits': PiwikQueryReportEventMetricUniqueVisits(**self.params),
                     'visit_duration': PiwikQueryReportEventMetricVisitDuration(**self.params),
                     'referrers': PiwikQueryReportEventMetricReferrers(**self.params),
                     'peak': PiwikQueryReportEventMetricPeakDateAndVisitors(**self.params)}
  
          for query_name, query in queries.iteritems():
              self.metrics[query_name] = query.get_result()
  
          self._fetch_contribution_info()
docs: Build the report by performing queries to Piwik