input: Write a function to find the maximum of three numbers.
  
  def max_of_three(a, b, c):
      if a > b and a > c:
          return a
      elif b > a and b > c:
          return b
      else:
          return c
  
  assert max_of_three(3, 4, 5) == 5
  assert max_of_three(7, 3, 1) == 7
  assert max_of_three(2, 8, 4) == 8
  assert max_of_three(5, 5, 5) == 5
output: def max_of_three(a, b, c):
      if a > b and a > c:
          return a
      elif b > a and b > c:
          return b
      else:
          return c