code: def change_existence(self, is_hidden):
          # type: (bool) -> None
          '''
          Change the ISO9660 existence flag of this Directory Record.
  
          Parameters:
           is_hidden - True if this Directory Record should be hidden, False otherwise.
          Returns:
           Nothing.
          '''
          if not self._initialized:
              raise pycdlibexception.PyCdlibInternalError('Directory Record not yet initialized')
  
          if is_hidden:
              self.file_flags |= (1 << self.FILE_FLAG_EXISTENCE_BIT)
          else:
              self.file_flags &= ~(1 << self.FILE_FLAG_EXISTENCE_BITf change_existence(self, is_hidden):
          # type: (bool) -> None
          '''
          Change the ISO9660 existence flag of this Directory Record.
  
          Parameters:
           is_hidden - True if this Directory Record should be hidden, False otherwise.
          Returns:
           Nothing.
          '''
          if not self._initialized:
              raise pycdlibexception.PyCdlibInternalError('Directory Record not yet initialized')
  
          if is_hidden:
              self.file_flags |= (1 << self.FILE_FLAG_EXISTENCE_BIT)
          else:
              self.file_flags &= ~(1 << self.FILE_FLAG_EXISTENCE_BIT)
docs: Change the ISO9660 existence flag of this Directory Record.
  
          Parameters:
           is_hidden - True if this Directory Record should be hidden, False otherwise.
          Returns:
           Nothing.