code: def test_fcompiler_flags(monkeypatch):
      monkeypatch.setenv("NPY_DISTUTILS_APPEND_FLAGS", "0")
      fc = numpy.distutils.fcompiler.new_fcompiler(compiler="none")
      flag_vars = fc.flag_vars.clone(lambda *args, **kwargs: None)
  
      for opt, envvar in customizable_flags:
          new_flag = "-dummy-{}-flag".format(opt)
          prev_flags = getattr(flag_vars, opt)
  
          monkeypatch.setenv(envvar, new_flag)
          new_flags = getattr(flag_vars, opt)
  
          monkeypatch.delenv(envvar)
          assert_(new_flags == [new_flag])
  
      monkeypatch.setenv("NPY_DISTUTILS_APPEND_FLAGS", "1")
  
      for opt, envvar in customizable_flags:
          new_flag = "-dummy-{}-flag".format(opt)
          prev_flags = getattr(flag_vars, opt)
          monkeypatch.setenv(envvar, new_flag)
          new_flags = getattr(flag_vars, opt)
  
          monkeypatch.delenv(envvar)
          if prev_flags is None:
              assert_(new_flags == [new_flag])
          else:
              assert_(new_flags == prev_flags + [new_flag])
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_fcompiler_flags(monkeypatch) without return types