<filename>game/apps/core/serializers/__init__.py
from game.apps.core.serializers.buildings import BuildingSerializer
from game.apps.core.serializers.system import SystemSerializer
from game.apps.core.serializers.system import SystemDetailsSerializer
from game.apps.core.serializers.planet import PlanetSerializer
from game.apps.core.serializers.planet import PlanetDetailsSerializer
from game.apps.core.serializers.tasks import TaskSerializer
<filename>game/apps/core/serializers/__init__.py
from game.apps.core.serializers.buildings import BuildingSerializer
from game.apps.core.serializers.system import SystemSerializer
from game.apps.core.serializers.system import SystemDetailsSerializer
from game.apps.core.serializers.planet import PlanetSerializer
from game.apps.core.serializers.planet import PlanetDetailsSerializer
from game.apps.core.serializers.tasks import TaskSerializer