def login(self, username=None, password=None):
        """Explicit Abode login."""
        if username is not None:
            self._cache[CONST.ID] = username
        if password is not None:
            self._cache[CONST.PASSWORD] = password

        if (self._cache[CONST.ID] is None or
                not isinstance(self._cache[CONST.ID], str)):
            raise AbodeAuthenticationException(ERROR.USERNAME)

        if (self._cache[CONST.PASSWORD] is None or
                not isinstance(self._cache[CONST.PASSWORD], str)):
            raise AbodeAuthenticationException(ERROR.PASSWORD)

        self._save_cache()

        self._token = None

        login_data = {
            CONST.ID: self._cache[CONST.ID],
            CONST.PASSWORD: self._cache[CONST.PASSWORD],
            CONST.UUID: self._cache[CONST.UUID]
        }

        response = self._session.post(CONST.LOGIN_URL, json=login_data)
        response_object = json.loads(response.text)

        oauth_token = self._session.get(CONST.OAUTH_TOKEN_URL)
        oauth_token_object = json.loads(oauth_token.text)

        if response.status_code != 200:
            raise AbodeAuthenticationException((response.status_code,
                                                response_object['message']))

        _LOGGER.debug("Login Response: %s", response.text)

        self._token = response_object['token']
        self._panel = response_object['panel']
        self._user = response_object['user']
        self._oauth_token = oauth_token_object['access_token']

        _LOGGER.info("Login successful")

        return True
Explicit Abode login.