"""`Singleton` provider example."""
from dependency_injector import containers, providers
class UserService:
...
class Container(containers.DeclarativeContainer):
user_service_provider = providers.Singleton(UserService)
if __name__ == '__main__':
container = Container()
user_service1 = container.user_service_provider()
user_service2 = container.user_service_provider()
assert user_service1 is user_service2