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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 id_to_atom(self, idx):
 """Returns the atom for a given original ligand ID. To do this, the ID is mapped to the protein first and then the atom returned. """

        mapped_idx = self.mapid(idx, 'reversed')
        return pybel.Atom(self.original_structure.GetAtom(mapped_idx))