code: def _analyze_root_causes(self):
          
          causes = {}
          for a in self.anomalies:
              try:
                  causes[a] = self.correlations[a][0]
              except IndexError:
                  raise exceptions.InvalidDataFormat('luminol.luminol: dict correlations contains empty list.')
          self.causes = causes
docs: Conduct root cause analysis.
          The first metric of the list is taken as the root cause right now.