Transform tag value

        - Collect value from tag
        - Transform Tag value
        - Assign new value for key

def process_transform(self, tag_value, resource_set):
        """
        Transform tag value

        - Collect value from tag
        - Transform Tag value
        - Assign new value for key
        """
        self.log.info("Transforming tag value on %s instances" % (
            len(resource_set)))
        key = self.data.get('key')

        c = utils.local_session(self.manager.session_factory).client('ec2')

        self.create_tag(
            c,
            [r[self.id_key] for r in resource_set if len(
                r.get('Tags', [])) < 50],
            key, tag_value)