input: Write a function to generate a random number between two given numbers, inclusive of both the numbers.
  assert random_number_generator(2, 5) in [2, 3, 4, 5]
  assert random_number_generator(0, 1) in [0, 1]
  assert random_number_generator(-5, 5) in range(-5, 6)
  assert random_number_generator(10, 15) in range(10, 16)
output: import random
  
  def random_number_generator(a, b):
      return random.randint(a, b)