input: Write a function to generate a random password of length 8, which consists of alphanumeric characters and at least one special character. It should check if the generated password contains at least one special character and if not, regenerate the password.
  assert generate_password() is not None
  assert len(generate_password()) == 8
  assert any([char in string.punctuation for char in generate_password()])
output: import random
  import string
  
  def generate_password():
      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