input: Write a function that takes in no input and generates a random string of length 6 using lowercase letters from the alphabet.
  assert random_string() == "abcdef"  # This is just an example and the actual output will be random.
  assert random_string() != "123456"
output: import random
  import string
  
  def random_string():
      return ''.join(random.choices(string.ascii_lowercase, k=6))