code: def test_fuse_roots():
      x = da.ones(10, chunks=(2,))
      y = da.zeros(10, chunks=(2,))
      z = (x + 1) + (2 * y**2)
      (zz,) = dask.optimize(z)
      # assert len(zz.dask) == 5
      assert (
          sum(map(dask.istask, zz.dask.values())) == 5
      )  # there are some aliases
      assert_eq(zz, z)
  
imports: from __future__ import annotations
  import pytest
  import numpy
  import dask
  import dask.array
  from dask.array.chunk import getitem
  from dask.array.core import getter
  from dask.array.core import getter_nofancy
  from dask.array.optimization import _is_getter_task, fuse_slice, optimize, optimize_blockwise, optimize_slices
  from dask.array.utils import assert_eq
  from dask.highlevelgraph import HighLevelGraph
  from dask.optimization import SubgraphCallable, fuse
  from dask.utils import SerializableLock
label_desc: Use image node_id 26 for calling a global function with example usage: test_fuse_roots() without return types