'Check if this user can be assigned to issues on username/repository.
:param str username: owner\'s username of the repository
:param str repository: name of the repository
:returns: True if the use can be assigned, False otherwise
:rtype: :class:`bool`'

def is_assignee_on(self, username, repository):

    url = self._build_url(u'repos', username, repository, u'assignees', self.login)
    return self._boolean(self._get(url), 204, 404)
