Startup Error:'utf-8' codec can't encode character '\udcef' in position 0: surrogates not allowed

[AlexLuya]

Blow error will come up every time,but extension works well.

Sorry, command-not-found has crashed! Please file a bug report at:
https://bugs.launchpad.net/command-not-found/+filebug
Please include the following information with the report:

command-not-found version: 0.3
Python version: 3.4.0 final 0
Distributor ID: Ubuntu
Description: Ubuntu 14.04.1 LTS
Release: 14.04
Codename: trusty
Exception information:

'utf-8' codec can't encode character '\udcef' in position 0: surrogates not allowed
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/CommandNotFound/util.py", line 24, in crash_guard
callback()
File "/usr/lib/command-not-found", line 90, in main
if not cnf.advise(args[0], options.ignore_installed) and not options.no_failure_msg:
File "/usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py", line 265, in advise
packages = self.getPackages(command)
File "/usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py", line 157, in getPackages
result.update([(pkg, db.component) for pkg in db.lookup(command)])
File "/usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py", line 85, in lookup
result = self.db.lookup(command)
File "/usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py", line 41, in lookup
key = key.encode('utf-8')
UnicodeEncodeError: 'utf-8' codec can't encode character '\udcef' in position 0: surrogates not allowed