fix: [stix2 export] Fixed class variable call
fix: [stix2 export] Fixed class variable call

Rafiot/MISP,devnull-/MISP,FloatingGhost/MISP,MISP/MISP,FIRSTdotorg/MISP,MISP/MISP,FloatingGhost/MISP,FIRSTdotorg/MISP,FloatingGhost/MISP,FloatingGhost/MISP,Rafiot/MISP,Rafiot/MISP,MISP/MISP,SteveClement/MISP,FIRSTdotorg/MISP,SteveClement/MISP,SteveClement/MISP,devnull-/MISP,devnull-/MISP,SteveClement/MISP,Rafiot/MISP,SteveClement/MISP,devnull-/MISP,FIRSTdotorg/MISP,MISP/MISP,MISP/MISP