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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 duplicate(self):
        '''
        Returns a copy of the current contact element.
        @returns: Contact
        '''
        return self.__class__(name=self.name, identifier=self.identifier,
                              phone=self.phone, require_id=self.__require_id,
                              address=self.address.duplicate())