How to use the solnlib.credentials.CredentialManager function in solnlib

def _get_manager(self, context):
        return CredentialManager(
            self._session_key,
            owner=self._endpoint.user,
            app=self._endpoint.app,
            realm=context.realm(),
            scheme=self._splunkd_info.scheme,
            host=self._splunkd_info.hostname,
            port=self._splunkd_info.port
        )

def _cred_mgr(self):
        if self._cred_manager is None:
            self._cred_manager = CredentialManager(
                self._session_key, self._app, owner=self._owner,
                realm=self._app, scheme=self._scheme, host=self._host,
                port=self._port, **self._context)

        return self._cred_manager

def decrypt_all(self, data):
        """
        :param data:
        :return: changed stanza list
        """
        credential_manager = CredentialManager(
            self._session_key,
            owner=self._endpoint.user,
            app=self._endpoint.app,
            realm=self._realm,
            scheme=self._splunkd_info.scheme,
            host=self._splunkd_info.hostname,
            port=self._splunkd_info.port
        )

        all_passwords = credential_manager._get_all_passwords()
        # filter by realm
        realm_passwords = [x for x in all_passwords if x['realm'] == self._realm]
        return self._merge_passwords(data, realm_passwords)