Filter with unicode strings

[baris]

if we try to make filter with a unicode string;

arule = Rule()

arule.filter = Filter("[road_type] = 'işlek'")

problem: no debug message but no filtering

---

arule = Rule()
arule.filter = Filter("[road_type] = 'i\351lek'")

problem: no debug message but no filtering

---

arule = Rule()
arule.filter = Filter("[road_type] = 'i\x15flek'")

problem : failed at := 'i\x15flek'