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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 diff(self, n, axis=0):
 """1st discrete difference Parameters n : int, number of periods to diff axis : int, axis to diff upon. default 0 Return ------ A list with a new TimeDeltaBlock. Note ---- The arguments here are mimicking shift so they are called correctly by apply. """

        if axis == 0:
            # Cannot currently calculate diff across multiple blocks since this
            # function is invoked via apply
            raise NotImplementedError
        new_values = (self.values - self.shift(n, axis=axis)[0].values).asi8

        # Reshape the new_values like how algos.diff does for timedelta data
        new_values = new_values.reshape(1, len(new_values))
        new_values = new_values.astype('timedelta64[ns]')
        return [TimeDeltaBlock(new_values, placement=self.mgr_locs.indexer)]