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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def channels(self):
 """The number of channels."""

        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