无法正常配置源

[Frisk-Colin]

执行apt-get update显示如下内容：
Traceback (most recent call last):
File "/usr/lib/cnf-update-db", line 27, in
col.create(db)
File "/usr/share/command-not-found/CommandNotFound/db/creator.py", line 95, in create
self._fill_commands(con)
File "/usr/share/command-not-found/CommandNotFound/db/creator.py", line 143, in _fill_commands
self._parse_single_contents_file(con, f, fp.stdout)
File "/usr/share/command-not-found/CommandNotFound/db/creator.py", line 282, in _parse_single_contents_file
priority = component_priorities[component]
KeyError: 'non-free-firmware'