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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 normalize(self, mag=1.):
 """Normalize a Channel, set `null` to 0 and the mag to given value. Parameters mag : float (optional) New value of mag. Default is 1. """


        def f(dataset, s, null, mag):
            dataset[s] -= null
            dataset[s] /= mag

        if self.signed:
            mag = self.mag() / mag
        else:
            mag = self.max() / mag
        self.chunkwise(f, null=self.null, mag=mag)
        self._null = 0