input: Write a function to generate a random password of length 8, which consists of alphanumeric characters and at least one special character. If the generated password does not contain any special character, the function should regenerate the password until it meets the requirement.
  
  assert generate_password() != generate_password() # to ensure the generated passwords are random
  assert len(generate_password()) == 8
  assert any([char in string.punctuation for char in generate_password()]) == True
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