input: Write a function to generate a random number between the given input numbers, including both start and stop. If the input numbers are the same, return that number.
  assert random_num(0, 10) in range(0, 11)
  assert random_num(5, 5) == 5
  assert random_num(-10, 10) in range(-10, 11)
output: import random
  
  def random_num(start, stop):
      if start == stop:
          return start
      return random.randint(start, stop)