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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 get_oxidation_state_decorated_structure(self):
 """ Returns an oxidation state decorated structure. Returns: Returns an oxidation state decorated structure. Requires POTCAR to be supplied. """

        structure = self.chgcar.structure
        charges = [-self.get_charge_transfer(i)
                   for i in range(len(structure))]
        structure.add_oxidation_state_by_site(charges)
        return structure