input: from typing import Callable
  
  def generate_random_number() -> int:
      """Generate a random 6-digit number.
      >>> generate_random_number() >= 100000 and generate_random_number() <= 999999
      True
      """
      import random
      return random.randint(100000, 999999)
output:     import random
      return random.randint(100000, 999999)