code: def test_meta_schedule_design_space_generator_union():
      mod = Matmul
      space_generator = ScheduleFn(sch_fn=schedule_matmul)
      space_generator_union = SpaceGeneratorUnion(
          [space_generator, space_generator]
      )
      design_spaces = space_generator_union.generate_design_space(mod)
      assert len(design_spaces) == 2
      for design_space in design_spaces:
          _check_correct(design_space)
  
file_path: tvm/tests/python/meta_schedule/test_meta_schedule_space_generator.py
imports: import math
  import pytest
  import tvm
  import tvm.testing
  from tvm._ffi.base import TVMError
  from tvm.meta_schedule.space_generator import PySpaceGenerator, ScheduleFn, SpaceGeneratorUnion
  from tvm.meta_schedule.tune_context import TuneContext
  from tvm.meta_schedule.utils import derived_object
  from tvm.script import tir
  from tvm.tir.schedule import Schedule
label_desc: Use image node_id 4 for calling a global function with example usage: test_meta_schedule_design_space_generator_union() without return types