def test_atleast_length_two(self): assert util.standard_error([1]) == None
def test_list_all_numbers(self): with pytest.raises(TypeError): util.standard_error([1,2,3,4,"2"])
def test_math(self): assert util.standard_error([1,2]) == 0.35355339059327373
def test_is_list(self): with pytest.raises(TypeError): util.standard_error("x")
def test_emptyList(self): assert util.standard_error([]) == None