'Update this pull request.
:param str title: (optional), title of the pull
:param str body: (optional), body of the pull request
:param str state: (optional), (\'open\', \'closed\')
:returns: bool'

@requires_auth
def update(self, title=None, body=None, state=None):

    data = {u'title': title, u'body': body, u'state': state}
    json = None
    self._remove_none(data)
    if data:
        json = self._json(self._patch(self._api, data=dumps(data)), 200)
    if json:
        self._update_attributes(json)
        return True
    return False
