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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _build_report(self):
 """Build the report by performing queries to Piwik"""

        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()