input: Write a function to generate a random number between 0 and 9. The function should return the randomly generated number.
  assert generate_random_number()==3
  assert generate_random_number()==7
  assert generate_random_number()==0
  assert generate_random_number()==9
  assert generate_random_number()==5
output: import random
  
  def generate_random_number():
      return random.randint(0, 9)