错误描述：将我的 Ubuntu 从 19.10 版本升级到 20.04LTS 后，我无法安装、更新或删除“Ubuntu 软件”中的任何软件。我还发现，如果我尝试通过“软件和更新”Ubuntu API 安装或修改某些内容，我的凭据窗口不会出现。我尝试启用 Canonical livepatch，但出现了以下错误：
org.freedesktop.DBus.Python.AttributeError: Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/softwareproperties/dbus/SoftwarePropertiesDBus.py", line 383, in _check_policykit_privilege
(is_auth, _, details) = self.polkit.CheckAuthorization(
File "/usr/lib/python3/dist-packages/dbus/proxies.py", line 141, in __call__
return self._connection.call_blocking(self._named_service,
File "/usr/lib/python3/dist-packages/dbus/connection.py", line 652, in call_blocking
reply_message = self.send_message_with_reply_and_block(
dbus.exceptions.DBusException: org.freedesktop.DBus.Error.ServiceUnknown: The name :1.274 was not provided by any .service files
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/dbus/service.py", line 711, in _message_cb
retval = candidate_method(self, *args, **keywords)
File "/usr/lib/python3/dist-packages/softwareproperties/dbus/SoftwarePropertiesDBus.py", line 345, in SetLivepatchEnabled
self._check_policykit_privilege(
File "/usr/lib/python3/dist-packages/softwareproperties/dbus/SoftwarePropertiesDBus.py", line 390, in _check_policykit_privilege
return self._check_polkit_privilege(sender, conn, privilege)
AttributeError: 'SoftwarePropertiesDBus' object has no attribute '_check_polkit_privilege'
有一些 API，例如 Sinaptic Package Manager，已经安装但现在不再起作用，但它们出现在我的已安装列表中；