code: def get_access_token(self) -> str:
          
          if self._service_token:
              return self._service_token
          if self._app_id and self._login and self._password:
              try:
                  if self.login():
                      url_params = self.auth_oauth2()
                      if 'access_token' in url_params:
                          return url_params['access_token']
              finally:
                  self.close()
docs: Returns the access token in case of successful authorization