def friendships_create(self, user_id=None, screen_name=None,
                           follow=None):
        """
        Allows the authenticating users to follow the specified user.

        https://dev.twitter.com/docs/api/1.1/post/friendships/create

        :param str user_id:
            The screen name of the user for whom to befriend. Required if
            ``screen_name`` isn't given.
        :param str screen_name:
            The ID of the user for whom to befriend. Required if ``user_id``
            isn't given.
        :param bool follow:
            Enable notifications for the target user.

        :returns:
            A dict containing the newly followed user.
        """
        params = {}
        set_str_param(params, 'user_id', user_id)
        set_str_param(params, 'screen_name', screen_name)
        set_bool_param(params, 'follow', follow)
        return self._post_api('friendships/create.json', params)