Get Tautulli sessions.

async def get_session_data(self):
        """Get Tautulli sessions."""
        cmd = 'get_activity'
        url = self.base_url + cmd
        try:
            async with async_timeout.timeout(8, loop=self._loop):
                response = await self._session.get(url)

            logger("Status from Tautulli: " + str(response.status))
            self.tautulli_session_data = await response.json()
            logger(self.tautulli_session_data)

        except (asyncio.TimeoutError, aiohttp.ClientError, socket.gaierror,
                AttributeError) as error:
            msg = "Can not load data from Tautulli: {} - {}".format(url, error)
            logger(msg, 40)