code: def test_wait_on_many(layers):
      t1, t2, cnt = demo_tuples(layers)
      out = wait_on(t1, {"x": [t2]})
      assert dask.compute(*out, scheduler="sync") == (
          (1, 2, 3),
          {"x": [(4, 5)]},
      )
      assert cnt.n == 5
  
imports: from __future__ import annotations
  import random
  import time
  from operator import add
  import pytest
  import dask
  import dask.bag
  from dask import delayed
  from dask.base import clone_key
  from dask.blockwise import Blockwise
  from dask.graph_manipulation import bind, checkpoint, chunks, clone, wait_on
  from dask.highlevelgraph import HighLevelGraph
  from dask.tests.test_base import Tuple
  from dask.utils_test import import_or_none
label_desc: Use image node_id 8 for calling a global function with example usage: test_wait_on_many(layers) without return types