input: from typing import List
  
  def generate_random_number(digits: int) -> int:
      """ Generate a random number with a specified number of digits.
      >>> generate_random_number(6)
      123456
      >>> generate_random_number(4)
      7890
      """
      return random.randint(10**(digits-1), 10**digits - 1)
output:     import random