input: Write a function to generate a random number between 0 and 9. The function should return the generated random number. If the function is called without any arguments, it should generate a new random number.
  
  assert generate_random_number()==0 # Example output, could be any number between 0 and 9
  assert generate_random_number()==9 # Example output, could be any number between 0 and 9
  assert generate_random_number()==3 # Example output, could be any number between 0 and 9
output: import random
  
  def generate_random_number():
      return random.randint(0, 9)