code: def channels(self):
          
          if self.mf.mode() == mad.MODE_SINGLE_CHANNEL:
              return 1
          elif self.mf.mode() in (mad.MODE_DUAL_CHANNEL,
                                  mad.MODE_JOINT_STEREO,
                                  mad.MODE_STEREO):
              return 2
          else:
              # Other mode?
              return 2
docs: The number of channels.