docs: def update_pzone(**kwargs):
      """Update pzone data in the DB"""
  
      pzone = PZone.objects.get(**kwargs)
  
      # get the data and loop through operate_on, applying them if necessary
      when = timezone.now()
      data = pzone.data
      for operation in pzone.operations.filter(when__lte=when, applied=False):
          data = operation.apply(data)
          operation.applied = True
          operation.save()
      pzone.data = data
  
      # create a history entry
      pzone.history.create(data=pzone.data)
  
      # save modified pzone, making transactions permanent
      pzone.save()