input: Write a function named `generate_random_number` that generates a random number within the range of [0, 10). Use the `random` module to achieve this.
  
  assert generate_random_number() in range(10)
  assert isinstance(generate_random_number(), int)
  assert generate_random_number() in range(10)
  assert isinstance(generate_random_number(), int)
output: import random
  
  def generate_random_number():
      return random.randint(0, 9)