input: Write a function `random_num` that generates a random integer between two given input numbers, inclusive. The function should take two parameters, `start` and `stop`, and return the random integer.
  
  assert random_num(0, 10) in range(0, 11)
  assert random_num(5, 15) in range(5, 16)
  assert random_num(-3, 3) in range(-3, 4)
  assert random_num(100, 200) in range(100, 201)
  assert random_num(-10, -5) in range(-10, -4)
output: import random
  
  def random_num(start, stop):
      return random.randint(start, stop)