code: def test_get_dependencies_task_none():
      # Regression test for https://github.com/dask/distributed/issues/2756
      dsk = {"foo": None}
      assert get_dependencies(dsk, task=dsk["foo"]) == set()
  
imports: import pickle
  from collections import namedtuple
  import pytest
  from flash.core.serve.dag.task import flatten, get, get_dependencies, get_deps, istask, literal, preorder_traversal, quote, subs
  from flash.core.serve.dag.utils_test import add, inc
  from flash.core.utilities.imports import _TOPIC_SERVE_AVAILABLE
label_desc: Use image node_id 10 for calling a global function with example usage: test_get_dependencies_task_none() without return types