Fix attribute errors, refs #313.
Fix attribute errors, refs #313.

ghukill/peewee,new-xiaji/peewee,coleifer/peewee,mackjoner/peewee,jarrahwu/peewee,softside/peewee,d1hotpep/peewee,jnovinger/peewee,ronyb29/peewee,new-xiaji/peewee,coreos/peewee,new-xiaji/peewee,coreos/peewee,coleifer/peewee,fuzeman/peewee,Dipsomaniac/peewee,Dipsomaniac/peewee,jarrahwu/peewee,Sunzhifeng/peewee,teserak/peewee,zhang625272514/peewee,Sunzhifeng/peewee,py4a/peewee,Dipsomaniac/peewee,fuzeman/peewee,zhang625272514/peewee,bopo/peewee,zhang625272514/peewee,d1hotpep/peewee,jarrahwu/peewee,coleifer/peewee,bopo/peewee,coreos/peewee,bopo/peewee,wenxer/peewee,Sunzhifeng/peewee,wenxer/peewee,stas/peewee,jnovinger/peewee,lez/peewee