input: Write a function to generate a random number between 0 and 9 using Python's `random` module. The function should return the generated random number.
  assert generate_random_number()==any_integer_between_0_and_9
  assert generate_random_number()==any_integer_between_0_and_9
  assert generate_random_number()==any_integer_between_0_and_9
  assert generate_random_number()==any_integer_between_0_and_9
  assert generate_random_number()==any_integer_between_0_and_9
output: import random
  
  def generate_random_number():
      return random.randint(0, 9)