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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 sum_over_energy(self):
 """ Reduce a counts cube to a counts map """

        # We sum over axis 0 in the array, and drop the energy binning in the
        # hpx object
        return HpxMap(np.sum(self.counts, axis=0), self.hpx.copy_and_drop_energy())