@property
  def listen_port(self):
    if self._daemon:
      return self._daemon.listen_port

    return None
Ticket fields that contain empty strings are stored as NULLs
dataset/ETHPy150Open ganeti/ganeti/lib/masterd/instance.py/DiskImport.listen_port--crossover with--dataset/ETHPy150Open edgewall/trac/trac/ticket/tests/model.py/TicketTestCase._test_empty_strings_stored_as_null