def test_mul_many_numbers():
c = Calc()
many = range(1, 6)
assert c.mul(*many) == 120
def test_mul_by_0_raises_exception():
c = Calc()
with pytest.raises(ValueError):
c.mul(3, 0)
def test_mul_two_numbers():
c = Calc()
assert c.mul(3, 10) == 30