def get_views_traffic(self, per=github.GithubObject.NotSet):
        """
        :calls: `GET /repos/:owner/:repo/traffic/views <https://developer.github.com/v3/repos/traffic/>`_
        :param per: string, must be one of day or week, day by default
        :rtype: None or list of :class:`github.View.View`
        """
        assert per is github.GithubObject.NotSet or (isinstance(per, (str, unicode)) and (per == "day" or per == "week")), "per must be day or week, day by default"
        url_parameters = dict()
        if per is not github.GithubObject.NotSet:
            url_parameters["per"] = per
        headers, data = self._requester.requestJsonAndCheck(
            "GET",
            self.url + "/traffic/views",
            parameters=url_parameters
        )
        if (isinstance(data, dict)) and ("views" in data) and (isinstance(data["views"], list)):
            data["views"] = [
                github.View.View(self._requester, headers, item, completed=True)
                for item in data["views"]
            ]
            return data