Use better syntax for checking callback existence
Use better syntax for checking callback existence

AtaraxiaEta/apm,pusateri/apm,atom/apm,Nikpolik/apm,VandeurenGlenn/apm,bronson/apm,jlord/apm,ethanp/apm,bcoe/apm,VandeurenGlenn/apm,bronson/apm,VandeurenGlenn/apm,bcoe/apm,pusateri/apm,VandeurenGlenn/apm,jlord/apm,Nikpolik/apm,bcoe/apm,atom/apm,gutsy/apm,bronson/apm,AtaraxiaEta/apm,ethanp/apm,Nikpolik/apm,gutsy/apm,Nikpolik/apm,atom/apm,jlord/apm,fscherwi/apm,pusateri/apm,AtaraxiaEta/apm,ethanp/apm,fscherwi/apm,bcoe/apm,pusateri/apm,AtaraxiaEta/apm,VandeurenGlenn/apm,fscherwi/apm,bcoe/apm,AtaraxiaEta/apm,pusateri/apm,atom/apm,fscherwi/apm,pusateri/apm,fscherwi/apm,gutsy/apm,fscherwi/apm,VandeurenGlenn/apm,jlord/apm,ethanp/apm,ethanp/apm,AtaraxiaEta/apm,jlord/apm,jlord/apm,bcoe/apm,ethanp/apm,gutsy/apm,bronson/apm