input: 
  from typing import List
  import random
  
  def generate_random_number() -> int:
      """ Generate a random 6-digit number.
      >>> generate_random_number()
      123456
      >>> generate_random_number()
      987654
      """
      return random.randint(100000, 999999)
  
output:     return random.randint(100000, 999999)