input: 
  from typing import List
  
  def generate_random_string(length: int) -> str:
      """ Generate a random string of a given length consisting of lowercase letters.
      >>> generate_random_string(6)
      'abcdef'
      >>> generate_random_string(6)
      'wxyzab'
      """
  
output:     import random
      import string
      
      return ''.join(random.choice(string.ascii_lowercase) for _ in range(length))