input: Write a python function to generate a random number within a specified range.
  assert 1 <= generate_random_number(1, 10) <= 10
  assert 50 <= generate_random_number(50, 100) <= 100
  assert -10 <= generate_random_number(-10, 0) <= 0
output: import random
  
  def generate_random_number(start, end):
      return random.randint(start, end)