input: Write a python function to generate a random integer between two given numbers.
  assert a <= random_int_generator(a, b) <= b
  assert a <= random_int_generator(a, b) <= b
  assert a <= random_int_generator(a, b) <= b
output: import random
  
  def random_int_generator(a, b):
      return random.randint(a, b)