def METHOD_NAME(self, number=-1, etag=None):
    """Iterate over the labels of every associated issue.
    .. versionchanged:: 0.9
        Add etag parameter.
    :param int number:
        (optional), number of labels to return. Default: -1 returns all
        available labels.
    :param str etag:
        (optional), ETag header from a previous response
    :returns:
        generator of labels
    :rtype:
        :class:`~github3.issues.label.ShortLabel`
    """
    url = self._build_url("labels", base_url=self._api)
    return self._iter(int(number), url, label.ShortLabel, etag=etag)