input: 
  def generate_password():
      """Generate a random password of length 8, consisting of alphanumeric characters 
      and at least one special character.
      >>> test_password = generate_password()
      >>> len(test_password) == 8
      True
      >>> any([char in string.punctuation for char in test_password])
      True
      """
  
output:     import random
      import string
  
      while True:
          password = ''.join(random.choices(string.ascii_letters + string.digits + string.punctuation, k=8))
          if any(char in string.punctuation for char in password):
              return password