code: def pytest_collection_modifyitems(config, items):
      skip_slow = pytest.mark.skip(
          reason="need --runslow option to run"
      )
      skip_sgpu = pytest.mark.skip(
          reason="need --run_single_gpu option to run"
      )
      custom_markers = dict(slow=skip_slow, single_gpu=skip_sgpu)
      if config.getoption("--runslow"):
          # --runslow given in cli: do not skip slow tests
          custom_markers.pop("slow", None)
      if config.getoption("--run_single_gpu", None):
          # --runslow given in cli: do not skip single-gpu tests
          custom_markers.pop("single_gpu", None)
      for item in items:
          for marker in custom_markers:
              if marker in item.keywords:
                  item.add_marker(custom_markers[marker])
  
imports: import pytest
label_desc: Use image node_id 3 for calling a global function with example usage: pytest_collection_modifyitems(config, items) without return types