input: Write a python function to generate a random number within a given range.
  assert 1 <= random_number_generator(1, 10) <= 10
  assert 20 <= random_number_generator(20, 30) <= 30
  assert 100 <= random_number_generator(100, 200) <= 200
output: import random
  
  def random_number_generator(start, end):
      return random.randint(start, end)