def search_users(self, query, sort=None, order=None, per_page=None,
                     text_match=False, number=-1, etag=None):
        params = {'q': query}
        headers = {}
        if sort in ('followers', 'repositories', 'joined'):
            params['sort'] = sort
        if order in ('asc', 'desc'):
            params['order'] = order
        if text_match:
            headers = {
                'Accept': 'application/vnd.github.v3.full.text-match+json'
                }
        url = self._build_url('search', 'users')
        return SearchIterator(number, url, UserSearchResult, self, params,
                              etag, headers)