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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 reorder_indices(self, indices_order):
        'reorder all the indices'
        # allow mixed index syntax like int
        indices_order, single = convert_index_to_keys(self.indices, indices_order)
        old_indices = force_list(self.indices.keys())

        if indices_order == old_indices: # no changes
            return

        if set(old_indices) != set(indices_order):
            raise KeyError('Keys in the new order do not match existing keys')

#        if len(old_indices) == 0: # already return since indices_order must equal to old_indices
#            return

        # must have more than 1 index to reorder
        new_idx = [old_indices.index(i) for i in indices_order]
        # reorder items
        items = [map(i.__getitem__, new_idx) for i in self.items()]
        self.clear(True)
        _MI_init(self, items, indices_order)