code: def calc_flag(self, sig=3.0):
          
   
          if len(self.gain.shape) == 4:
              gamp = n.abs(self.gain).mean(axis=0)   # mean gain amp for each ant over time
          elif len(self.gain.shape) == 3:
              gamp = n.abs(self.gain)   # gain amp for selected time
  
  #        badgain = n.where(gamp < gamp.mean() - sig*gamp.std())
          badgain = n.where( (gamp < gamp.mean() - sig*gamp.std()) | gamp.mask)
          self.logger.info('Flagging low/bad gains for ant/spw/pol: %s %s %s' % (str(self.antnum[badgain[0]]), str(badgain[1]), str(badgain[2])))
  
          badants = badgain
          return badants
docs: Calculates antennas to flag, based on bad gain and bp solutions.