Adds the list of tags to current tags. (flickr.photos.addtags)

def addTags(self, tags):
        """Adds the list of tags to current tags. (flickr.photos.addtags)
        """
        method = 'flickr.photos.addTags'
        if isinstance(tags, list):
            tags = uniq(tags)

        _dopost(method, auth=True, photo_id=self.id, tags=tags)
        #load properties again
        self._load_properties()