docs: def create_captcha(self, captcha_type="image", ssl=None, content_id=None):
          """Creates a CAPTCHA to be served to the end-user.
          
          Keyword arguments:
          captcha_type -- Type of CAPTCHA to create: "image" or "audio". Defaults to "image".
          ssl -- True for a CAPTCHA served over https. Defaults to False.
          content_id -- Unique identifier of the content to link the CAPTCHA to, in case the content was unsure.
          
          Returns:
          captcha_id -- Unique identifier of the CAPTCHA created.
          url -- Path to the CAPTCHA resource to be served to the end-user.
          """
          create_captcha_endpoint = Template("${rest_root}/captcha")
          url = create_captcha_endpoint.substitute(rest_root=self._rest_root)
          
          data = {"type": captcha_type}
          if ssl:
              data["ssl"] = 1 if ssl else 0
          if content_id:
              data["contentId"] = content_id
          
          response = self.__post_request(url, data)
          return response["captcha"]["id"], response["captcha"]["url"]