input: def generate_password() -> str:
      """Generate a random password of length 8, which consists of alphanumeric characters and at least one special character.
      >>> generate_password()
      'A1b2!@c3'
      >>> generate_password()
      '4$5D6e7F'
      """
output:     import random
      import string
  
      characters = string.ascii_letters + string.digits
      special_characters = "!@#$%^&*()_+"
      
      while True:
          password = ''.join(random.choice(characters) for _ in range(7))
          password += random.choice(special_characters)
          if any(c in special_characters for c in password):
              return ''.join(random.sample(password, len(password)))