fix: fixed issue for events with no attributes
fix: fixed issue for events with no attributes

SteveClement/MISP,MISP/MISP,FIRSTdotorg/MISP,TheDr1ver/MISP,FloatingGhost/MISP,Rafiot/MISP,TheDr1ver/MISP,FIRSTdotorg/MISP,MISP/MISP,FloatingGhost/MISP,devnull-/MISP,devnull-/MISP,SteveClement/MISP,SteveClement/MISP,SteveClement/MISP,Rafiot/MISP,SteveClement/MISP,MISP/MISP,devnull-/MISP,FloatingGhost/MISP,Rafiot/MISP,MISP/MISP,devnull-/MISP,Rafiot/MISP,FloatingGhost/MISP,TheDr1ver/MISP,FIRSTdotorg/MISP,TheDr1ver/MISP,MISP/MISP,FIRSTdotorg/MISP