input: Write a python function to calculate the hypotenuse of a right-angled triangle given the lengths of the other two sides.
  assert calc_hypotenuse(3, 4) == 5.0
  assert calc_hypotenuse(5, 12) == 13.0
  assert calc_hypotenuse(8, 15) == 17.0
output: def calc_hypotenuse(a, b):
      return (a**2 + b**2) ** 0.5