old_contents: """Mission configuration model."""
  
  import logging
  from auvsi_suas.models.fly_zone import FlyZone
  from auvsi_suas.models.gps_position import GpsPosition
  from auvsi_suas.models.odlc import Odlc
  from auvsi_suas.models.stationary_obstacle import StationaryObstacle
  from auvsi_suas.models.waypoint import Waypoint
  from django.contrib import admin
  from django.core import validators
  from django.db import models
  
  logger = logging.getLogger(__name__)
  
  
  class MissionConfig(models.Model):
      """The details for the mission."""
  
      # The home position for use as a reference point. Should be the tents.
      home_pos = models.ForeignKey(
          GpsPosition,
          related_name="missionconfig_home_pos",
          on_delete=models.CASCADE)
      # Valid areas for the UAS to fly.
      fly_zones = models.ManyToManyField(FlyZone)
      # The waypoints that define the mission waypoint path
      mission_waypoints = models.ManyToManyField(
          Waypoint, related_name='missionconfig_mission_waypoints')
      # The polygon that defines the search grid.
      search_grid_points = models.ManyToManyField(
          Waypoint, related_name='missionconfig_search_grid_points')
      # The judge created objects for detection.
      odlcs = models.ManyToManyField(Odlc, related_name='missionconfig_odlc')
      # The last known position of the emergent object.
      emergent_last_known_pos = models.ForeignKey(
          GpsPosition,
          related_name='missionconfig_emergent_last_known_pos',
          on_delete=models.CASCADE)
      # Off-axis object position.
      off_axis_odlc_pos = models.ForeignKey(
          GpsPosition,
          related_name='missionconfig_off_axis_odlc_pos',
          on_delete=models.CASCADE)
      # The air drop position.
      air_drop_pos = models.ForeignKey(
          GpsPosition,
          related_name='missionconfig_air_drop_pos',
          on_delete=models.CASCADE)
      # The stationary obstacles.
      stationary_obstacles = models.ManyToManyField(StationaryObstacle)
  
      def __str__(self):
          return 'Mission %d' % self.pk
  
  
  @admin.register(MissionConfig)
  class MissionConfigModelAdmin(admin.ModelAdmin):
      raw_id_fields = ("home_pos", "emergent_last_known_pos",
                       "off_axis_odlc_pos", "air_drop_pos")
      filter_horizontal = ("fly_zones", "mission_waypoints",
                           "search_grid_points", "odlcs", "stationary_obstacles")
      list_display = ('pk', 'home_pos', )
  
new_contents: """Mission configuration model."""
  
  import logging
  from auvsi_suas.models.fly_zone import FlyZone
  from auvsi_suas.models.gps_position import GpsPosition
  from auvsi_suas.models.odlc import Odlc
  from auvsi_suas.models.stationary_obstacle import StationaryObstacle
  from auvsi_suas.models.waypoint import Waypoint
  from django.contrib import admin
  from django.core import validators
  from django.db import models
  
  logger = logging.getLogger(__name__)
  
  
  class MissionConfig(models.Model):
      """The details for the mission."""
  
      # The home position for use as a reference point. Should be the tents.
      home_pos = models.ForeignKey(
          GpsPosition,
          related_name="missionconfig_home_pos",
          on_delete=models.CASCADE)
      # Valid areas for the UAS to fly.
      fly_zones = models.ManyToManyField(FlyZone)
      # The waypoints that define the mission waypoint path
      mission_waypoints = models.ManyToManyField(
          Waypoint, related_name='missionconfig_mission_waypoints')
      # The polygon that defines the search grid.
      search_grid_points = models.ManyToManyField(
          Waypoint, related_name='missionconfig_search_grid_points')
      # The judge created objects for detection.
      odlcs = models.ManyToManyField(
          Odlc, related_name='missionconfig_odlc', blank=True)
      # The last known position of the emergent object.
      emergent_last_known_pos = models.ForeignKey(
          GpsPosition,
          related_name='missionconfig_emergent_last_known_pos',
          on_delete=models.CASCADE)
      # Off-axis object position.
      off_axis_odlc_pos = models.ForeignKey(
          GpsPosition,
          related_name='missionconfig_off_axis_odlc_pos',
          on_delete=models.CASCADE)
      # The air drop position.
      air_drop_pos = models.ForeignKey(
          GpsPosition,
          related_name='missionconfig_air_drop_pos',
          on_delete=models.CASCADE)
      # The stationary obstacles.
      stationary_obstacles = models.ManyToManyField(StationaryObstacle)
  
      def __str__(self):
          return 'Mission %d' % self.pk
  
  
  @admin.register(MissionConfig)
  class MissionConfigModelAdmin(admin.ModelAdmin):
      raw_id_fields = ("home_pos", "emergent_last_known_pos",
                       "off_axis_odlc_pos", "air_drop_pos")
      filter_horizontal = ("fly_zones", "mission_waypoints",
                           "search_grid_points", "odlcs", "stationary_obstacles")
      list_display = ('pk', 'home_pos', )
  
subject: Add blank=True to MissionConfig.odlcs.