[PEP8] Cleanup core.py
[PEP8] Cleanup core.py

owtf/owtf,DarKnight--/owtf,DarKnight24/owtf,DarKnight--/owtf,DarKnight--/owtf,owtf/owtf,owtf/owtf,DarKnight24/owtf,DarKnight--/owtf,owtf/owtf,DarKnight24/owtf,DarKnight24/owtf,owtf/owtf