input: Write a python function to find the maximum of three numbers using a lambda function.
  assert max_func(3, 12, 7) == 12
  assert max_func(10, 5, 8) == 10
  assert max_func(4, 4, 4) == 4
output: def max_func(a, b, c):
      return (lambda x, y, z: x if x > y and x > z else y if y > z else z)(a, b, c)