def validate(self):
        """
        Perform validation check on properties.
        """
        if not self.api_token or not self.api_token_secret:
            raise ImproperlyConfigured("'api_token' and 'api_token_secret' are required for authentication.")

        if self.response_type not in ["json", "pson", "xml", "debug", None]:
            raise ImproperlyConfigured("'%s' is an invalid response_type" % self.response_type)
Perform validation check on properties.