эта ошибка после включения deb
http://in.archive.ubuntu.com/ubuntu bionic main universe in sources.list
Get:6 http://in.archive.ubuntu.com/ubuntu bionic InRelease [242 kB]
Err:6 http://in.archive.ubuntu.com/ubuntu bionic InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 3B4FE6ACC0B21F32
Reading package lists... Done
помогите пожалуйста