Fix reference counting bug
Fix reference counting bug

qwhelan/asv,airspeed-velocity/asv,pv/asv,pv/asv,qwhelan/asv,spacetelescope/asv,spacetelescope/asv,qwhelan/asv,airspeed-velocity/asv,pv/asv,spacetelescope/asv,pv/asv,spacetelescope/asv,airspeed-velocity/asv,qwhelan/asv,airspeed-velocity/asv