Call the API.

async def api_call(self, endpoint):
        """Call the API."""
        data = None
        if self.session is None:
            self.session = aiohttp.ClientSession()
        try:
            async with async_timeout.timeout(5, loop=self.loop):
                response = await self.session.get(endpoint, headers=HEADERS)
                data = await response.json()
        except aiohttp.ClientError as error:
            LOGGER.error('Error connecting to Ruter, %s', error)
        except asyncio.TimeoutError as error:
            LOGGER.debug('Timeout connecting to Ruter, %s', error)
        return data