[ibus][SunPinyin] Failed to open Preferences

[Yung Shen]

on 17.04 with latest `$ apt full-upgrade`

Open setting gui via terminal:
$ ibus-setup

goto 'Input Method' tab

add 'SunPinyin'

try to open 'Preferences'

and see following error messages in terminal:

Traceback (most recent call last):
  File "/usr/share//ibus-sunpinyin/setup/main.py", line 42, in <module>
    import ibus
ImportError: No module named ibus

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: ibus-sunpinyin 2.0.3-5build3
ProcVersionSignature: Ubuntu 4.10.0-22.24-generic 4.10.15
Uname: Linux 4.10.0-22-generic x86_64
ApportVersion: 2.20.4-0ubuntu4.1
Architecture: amd64
CurrentDesktop: GNOME
Date: Tue Jun 13 18:08:38 2017
InstallationDate: Installed on 2017-05-26 (17 days ago)
InstallationMedia: Ubuntu-GNOME 17.04 "Zesty Zapus" - Release amd64 (20170412)
SourcePackage: ibus-sunpinyin
UpgradeStatus: No upgrade log present (probably fresh install)