input: Write a python function to find the maximum of three numbers.
  assert get_max(2, 4, 3) == 4
  assert get_max(10, 5, 7) == 10
  assert get_max(1, 1, 1) == 1
  assert get_max(-5, -10, -3) == -3
output: def get_max(a, b, c):
      return max(a, b, c)