@subscription_substitution_tag.setter<EOL><INDENT>def subscription_substitution_tag(self, value):<DEDENT>
self._subscription_substitution_tag = value<EOL>
A tag that will be replaced with the unsubscribe URL. for example:
           [unsubscribe_url]. If this parameter is used, it will override both
           the text and html parameters. The URL of the link will be placed at
           the substitution tag's location, with no additional formatting.

        :param value: A tag that will be replaced with the unsubscribe URL.
                      for example: [unsubscribe_url]. If this parameter is
                      used, it will override both the text and html parameters.
                      The URL of the link will be placed at the substitution
                      tag's location, with no additional formatting.
        :type value: string