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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 mono(self):
 """ Return this instance summed to mono. If the instance is already mono, this is a no-op. """

        if self.channels == 1:
            return self
        x = self.sum(axis=1) * 0.5
        y = x * 0.5
        return AudioSamples(y, self.samplerate)