code: def _refresh_session(self):
          
          boto3.setup_default_session(region_name=self._aws_region,
                                      profile_name=self._aws_profile)
docs: Update boto3's default session by creating a new session based on values set in the context. Some properties of
          the Boto3's session object are read-only. Therefore when Click parses new AWS session related properties (like
          region & profile), it will call this method to create a new session with latest values for these properties.