def METHOD_NAME(self, task):
    """Return all direct downstream dependencies of the task."""
    # Cache the downstream dependencies for faster lookups.
    if not hasattr(self, "_downstream_dependencies"):
        downstream_dependencies = defaultdict(list)
        for dag in self.dags:
            for _task in dag.tasks:
                _task.with_upstream_dependencies(self)
                for upstream_dependency in (
                    _task.depends_on + _task.upstream_dependencies
                ):
                    downstream_dependencies[upstream_dependency.task_key].append(
                        _task.to_ref(self)
                    )
        self._downstream_dependencies = downstream_dependencies
    return self._downstream_dependencies[task.task_key]