input: Write a function to find the maximum of three numbers. The function should accept three parameters and return the largest of the three numbers.
  assert max_of_three(3, 4, 5) == 5
  assert max_of_three(7, 2, 3) == 7
  assert max_of_three(1, 1, 1) == 1
  assert max_of_three(-1, -5, -3) == -1
  assert max_of_three(0, 0, 0) == 0
output: def max_of_three(a, b, c):
      return max(a, b, c)