POST /oauth/v2/token

        Get a new token

        :param host: host of the service
        :param params: will contain :

        params = {"grant_type": "password",
                  "client_id": "a string",
                  "client_secret": "a string",
                  "username": "a login",
                  "password": "a password"}

        :return: access token

async def get_token(cls, host, **params):
        """
        POST /oauth/v2/token

        Get a new token

        :param host: host of the service
        :param params: will contain :

        params = {"grant_type": "password",
                  "client_id": "a string",
                  "client_secret": "a string",
                  "username": "a login",
                  "password": "a password"}

        :return: access token
        """
        params['grant_type'] = "password"
        path = "/oauth/v2/token"
        async with aiohttp.ClientSession() as sess:
            async with sess.post(host + path, data=params) as resp:
                data = await cls.handle_json_response(resp)
                return data.get("access_token")