input: Write a python function to generate a random number between two given numbers.
  assert 1 <= random_between_nums(1, 10) <= 10
  assert 50 <= random_between_nums(50, 100) <= 100
  assert -10 <= random_between_nums(-10, 10) <= 10
output: import random
  
  def random_between_nums(a, b):
      return random.randint(a, b)