code: def test_inline_functions():
      x, y, i, d = "xyid"
      dsk = {
          "out": (add, i, d),
          i: (inc, x),
          d: (double, y),
          x: 1,
          y: 1,
      }
  
      result = inline_functions(dsk, [], fast_functions={inc})
      expected = {"out": (add, (inc, x), d), d: (double, y), x: 1, y: 1}
      assert result == expected
  
imports: import itertools
  import pickle
  from functools import partial
  import pytest
  from flash.core.serve.dag.optimization import SubgraphCallable, cull, functions_of, fuse, fuse_linear, inline, inline_functions
  from flash.core.serve.dag.task import get, get_dependencies
  from flash.core.serve.dag.utils import apply, partial_by_order
  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 8 for calling a global function with example usage: test_inline_functions() without return types