input: Write a function to generate a random number between the given input numbers. The function should take two parameters: start and stop, and return a random integer between start and stop (inclusive).
  
  assert random_num(0, 10)>=0 and random_num(0, 10)<=10
  assert random_num(10, 20)>=10 and random_num(10, 20)<=20
  assert random_num(-5, 5)>=-5 and random_num(-5, 5)<=5
output: import random
  
  def random_num(start, stop):
      return random.randint(start, stop)