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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_pvd(self):
        # type: () -> None
        '''
        A method to add a duplicate PVD to the ISO.  This is a mostly useless
        feature allowed by Ecma-119 to have duplicate PVDs to avoid possible
        corruption.

        Parameters:
         None.
        Returns:
         Nothing.
        '''
        if not self._initialized:
            raise pycdlibexception.PyCdlibInvalidInput('This object is not yet initialized; call either open() or new() to create an ISO')

        pvd = headervd.PrimaryOrSupplementaryVD(headervd.VOLUME_DESCRIPTOR_TYPE_PRIMARY)
        pvd.copy(self.pvd)
        self.pvds.append(pvd)

        self._finish_add(self.pvd.logical_block_size(), 0)