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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def fetchUnread(self):
 """ Get the unread thread list :return: List of unread thread ids :rtype: list :raises: FBchatException if request failed """

        form = {
            "folders[0]": "inbox",
            "client": "mercury",
            "last_action_timestamp": now() - 60 * 1000
            # 'last_action_timestamp': 0
        }
        j = self._post(
            self.req_url.UNREAD_THREADS, form, fix_request=True, as_json=True
        )

        payload = j["payload"]["unread_thread_fbids"][0]
        return payload["thread_fbids"] + payload["other_user_fbids"]