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