Returns a fully qualified URL

def _build_url(self, endpoint):
        """ Returns a fully qualified URL """
        server = None
        if "://" in endpoint:
            # looks like an url, let's break it down
            server, endpoint = self._deconstruct_url(endpoint)

        endpoint = endpoint.lstrip("/")
        url = "{proto}://{server}/{endpoint}".format(
            proto=self.protocol,
            server=self.client.server if server is None else server,
            endpoint=endpoint,
        )
        return url