def METHOD_NAME(cell, arg2):
    """Test cellify decorator with provided arguments"""
    if isinstance(arg2, float):
        with pytest.raises(ValueError):
            result_cell, result_arg2 = _function2_arg(cell, arg2=arg2)
    else:
        result_cell, result_arg2 = _function2_arg(cell, arg2=arg2)
        # cell argument should be unchanged
        assert result_cell == cell
        # check arg2 coercion to gemmi instance
        if arg2 is None:
            assert result_arg2 is None
        elif isinstance(arg2, gemmi.UnitCell):
            assert np.array_equal(result_arg2.parameters, arg2.parameters)
        else:
            assert isinstance(result_arg2, gemmi.UnitCell)
            expected = gemmi.UnitCell(*arg2)
            assert np.array_equal(result_arg2.parameters, expected.parameters)