'Lookup friendship status for user to authed user.
Users may be specified either as lists of either user_ids,
screen_names, or twitter.User objects. The list of users that
are queried is the union of all specified parameters.
Up to 100 users may be specified.
Args:
user_id (int, User, or list of ints or Users, optional):
A list of user_ids to retrieve extended information.
screen_name (string, User, or list of strings or Users, optional):
A list of screen_names to retrieve extended information.
Returns:
list: A list of twitter.UserStatus instance representing the
friendship status between the specified users and the authenticated
user.'

def LookupFriendship(self, user_id=None, screen_name=None):

    url = ('%s/friendships/lookup.json' % self.base_url)
    parameters = {}
    if user_id:
        if (isinstance(user_id, list) or isinstance(user_id, tuple)):
            uids = list()
            for user in user_id:
                if isinstance(user, User):
                    uids.append(user.id)
                else:
                    uids.append(enf_type('user_id', int, user))
            parameters['user_id'] = ','.join([str(uid) for uid in uids])
        elif isinstance(user_id, User):
            parameters['user_id'] = user_id.id
        else:
            parameters['user_id'] = enf_type('user_id', int, user_id)
    if screen_name:
        if (isinstance(screen_name, list) or isinstance(screen_name, tuple)):
            sn_list = list()
            for user in screen_name:
                if isinstance(user, User):
                    sn_list.append(user.screen_name)
                else:
                    sn_list.append(enf_type('screen_name', str, user))
            parameters['screen_name'] = ','.join(sn_list)
        elif isinstance(screen_name, User):
            parameters['screen_name'] = screen_name.screen_name
        else:
            parameters['screen_name'] = enf_type('screen_name', str, screen_name)
    if ((not user_id) and (not screen_name)):
        raise TwitterError('Specify    at    least    one    of    user_id    or    screen_name.')
    resp = self._RequestUrl(url, 'GET', data=parameters)
    data = self._ParseAndCheckTwitter(resp.content.decode('utf-8'))
    return [UserStatus.NewFromJsonDict(x) for x in data]
