code: def intersection(self):
          
          isegs = reduce(operator.and_, self.values())
          isegs.name = ' & '.join(self.keys())
          return isegs
docs: Return the intersection of all flags in this dict
  
          Returns
          -------
          intersection : `DataQualityFlag`
              a new `DataQualityFlag` who's active and known segments
              are the intersection of those of the values of this dict