code: 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(), 0f 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)
docs: 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.