input: Write a function to generate and return a random integer between 0 and 9 (inclusive of 0 and inclusive of 9). The function should use Python's built-in random module.
  
  def generate_random_number():
      import random
      return random.randint(0, 9)
  
  assert generate_random_number() in range(10)
  assert isinstance(generate_random_number(), int)
output: def generate_random_number():
      import random
      return random.randint(0, 9)