Only iterate over collections if they exist! (ROOT-6311, ROOT-6307)
Only iterate over collections if they exist! (ROOT-6311, ROOT-6307)

georgtroska/root,sbinet/cxx-root,simonpf/root,satyarth934/root,mhuwiler/rootauto,vukasinmilosevic/root,arch1tect0r/root,mattkretz/root,olifre/root,omazapa/root-old,sawenzel/root,satyarth934/root,vukasinmilosevic/root,jrtomps/root,karies/root,thomaskeck/root,Y--/root,omazapa/root-old,Duraznos/root,lgiommi/root,CristinaCristescu/root,agarciamontoro/root,pspe/root,karies/root,jrtomps/root,satyarth934/root,esakellari/my_root_for_test,nilqed/root,buuck/root,veprbl/root,buuck/root,georgtroska/root,sbinet/cxx-root,zzxuanyuan/root-compressor-dummy,smarinac/root,gganis/root,abhinavmoudgil95/root,sbinet/cxx-root,Duraznos/root,omazapa/root,esakellari/root,veprbl/root,CristinaCristescu/root,esakellari/root,perovic/root,abhinavmoudgil95/root,sbinet/cxx-root,thomaskeck/root,karies/root,dfunke/root,sbinet/cxx-root,gganis/root,root-mirror/root,sirinath/root,gbitzes/root,omazapa/root,buuck/root,0x0all/ROOT,sawenzel/root,smarinac/root,gbitzes/root,Y--/root,mattkretz/root,esakellari/root,satyarth934/root,krafczyk/root,zzxuanyuan/root,lgiommi/root,buuck/root,gbitzes/root,mhuwiler/rootauto,vukasinmilosevic/root,gbitzes/root,veprbl/root,perovic/root,0x0all/ROOT,buuck/root,Y--/root,veprbl/root,zzxuanyuan/root,krafczyk/root,beniz/root,arch1tect0r/root,Y--/root,krafczyk/root,dfunke/root,evgeny-boger/root,karies/root,Y--/root,sirinath/root,lgiommi/root,root-mirror/root,BerserkerTroll/root,abhinavmoudgil95/root,bbockelm/root,olifre/root,root-mirror/root,mkret2/root,davidlt/root,thomaskeck/root,agarciamontoro/root,krafczyk/root,karies/root,Duraznos/root,jrtomps/root,nilqed/root,mattkretz/root,georgtroska/root,smarinac/root,simonpf/root,Duraznos/root,abhinavmoudgil95/root,CristinaCristescu/root,Y--/root,BerserkerTroll/root,krafczyk/root,esakellari/my_root_for_test,vukasinmilosevic/root,davidlt/root,Duraznos/root,abhinavmoudgil95/root,veprbl/root,sawenzel/root,bbockelm/root,karies/root,nilqed/root,agarciamontoro/root,georgtroska/root,zzxuanyuan/root-compressor-dummy,0x0all/ROOT,mattkretz/root,sbinet/cxx-root,omazapa/root-old,sawenzel/root,abhinavmoudgil95/root,sirinath/root,omazapa/root-old,thomaskeck/root,nilqed/root,davidlt/root,zzxuanyuan/root,sirinath/root,pspe/root,0x0all/ROOT,gganis/root,zzxuanyuan/root-compressor-dummy,jrtomps/root,zzxuanyuan/root,krafczyk/root,BerserkerTroll/root,bbockelm/root,dfunke/root,buuck/root,beniz/root,0x0all/ROOT,beniz/root,omazapa/root,simonpf/root,smarinac/root,sbinet/cxx-root,beniz/root,CristinaCristescu/root,BerserkerTroll/root,abhinavmoudgil95/root,simonpf/root,nilqed/root,Duraznos/root,esakellari/root,zzxuanyuan/root,nilqed/root,bbockelm/root,dfunke/root,thomaskeck/root,sawenzel/root,CristinaCristescu/root,davidlt/root,gganis/root,esakellari/my_root_for_test,thomaskeck/root,smarinac/root,sbinet/cxx-root,root-mirror/root,pspe/root,georgtroska/root,nilqed/root,krafczyk/root,gbitzes/root,mattkretz/root,abhinavmoudgil95/root,pspe/root,agarciamontoro/root,buuck/root,zzxuanyuan/root,simonpf/root,CristinaCristescu/root,beniz/root,BerserkerTroll/root,esakellari/root,arch1tect0r/root,georgtroska/root,dfunke/root,simonpf/root,bbockelm/root,bbockelm/root,lgiommi/root,Y--/root,CristinaCristescu/root,buuck/root,nilqed/root,esakellari/my_root_for_test,evgeny-boger/root,vukasinmilosevic/root,sirinath/root,gganis/root,olifre/root,zzxuanyuan/root,dfunke/root,mkret2/root,gganis/root,esakellari/my_root_for_test,arch1tect0r/root,esakellari/my_root_for_test,zzxuanyuan/root-compressor-dummy,buuck/root,agarciamontoro/root,agarciamontoro/root,lgiommi/root,krafczyk/root,sirinath/root,georgtroska/root,bbockelm/root,mattkretz/root,veprbl/root,beniz/root,evgeny-boger/root,mhuwiler/rootauto,karies/root,mhuwiler/rootauto,gbitzes/root,simonpf/root,bbockelm/root,jrtomps/root,perovic/root,beniz/root,dfunke/root,perovic/root,zzxuanyuan/root,zzxuanyuan/root,root-mirror/root,dfunke/root,root-mirror/root,omazapa/root-old,smarinac/root,esakellari/root,mattkretz/root,abhinavmoudgil95/root,gganis/root,satyarth934/root,buuck/root,mhuwiler/rootauto,mkret2/root,evgeny-boger/root,vukasinmilosevic/root,smarinac/root,karies/root,bbockelm/root,krafczyk/root,sawenzel/root,buuck/root,dfunke/root,gganis/root,jrtomps/root,arch1tect0r/root,jrtomps/root,BerserkerTroll/root,omazapa/root-old,evgeny-boger/root,esakellari/my_root_for_test,pspe/root,evgeny-boger/root,evgeny-boger/root,pspe/root,gbitzes/root,georgtroska/root,satyarth934/root,sbinet/cxx-root,olifre/root,mkret2/root,vukasinmilosevic/root,mhuwiler/rootauto,perovic/root,beniz/root,0x0all/ROOT,olifre/root,Duraznos/root,esakellari/my_root_for_test,mkret2/root,nilqed/root,mkret2/root,zzxuanyuan/root-compressor-dummy,arch1tect0r/root,veprbl/root,olifre/root,Duraznos/root,vukasinmilosevic/root,abhinavmoudgil95/root,root-mirror/root,mattkretz/root,vukasinmilosevic/root,pspe/root,0x0all/ROOT,zzxuanyuan/root-compressor-dummy,jrtomps/root,perovic/root,mkret2/root,zzxuanyuan/root-compressor-dummy,pspe/root,omazapa/root,mhuwiler/rootauto,veprbl/root,omazapa/root,arch1tect0r/root,lgiommi/root,bbockelm/root,beniz/root,agarciamontoro/root,perovic/root,root-mirror/root,evgeny-boger/root,mkret2/root,smarinac/root,smarinac/root,evgeny-boger/root,agarciamontoro/root,olifre/root,davidlt/root,esakellari/root,Duraznos/root,BerserkerTroll/root,BerserkerTroll/root,lgiommi/root,esakellari/root,karies/root,jrtomps/root,sirinath/root,abhinavmoudgil95/root,dfunke/root,thomaskeck/root,nilqed/root,simonpf/root,zzxuanyuan/root,Y--/root,simonpf/root,sawenzel/root,perovic/root,omazapa/root-old,Y--/root,zzxuanyuan/root,satyarth934/root,davidlt/root,CristinaCristescu/root,arch1tect0r/root,veprbl/root,omazapa/root-old,agarciamontoro/root,davidlt/root,omazapa/root-old,davidlt/root,smarinac/root,thomaskeck/root,0x0all/ROOT,thomaskeck/root,sirinath/root,omazapa/root,bbockelm/root,sawenzel/root,sirinath/root,davidlt/root,gbitzes/root,sawenzel/root,pspe/root,agarciamontoro/root,esakellari/root,jrtomps/root,thomaskeck/root,davidlt/root,davidlt/root,zzxuanyuan/root-compressor-dummy,lgiommi/root,mhuwiler/rootauto,perovic/root,sirinath/root,simonpf/root,omazapa/root,zzxuanyuan/root,mkret2/root,satyarth934/root,mattkretz/root,Y--/root,georgtroska/root,vukasinmilosevic/root,pspe/root,perovic/root,gganis/root,esakellari/my_root_for_test,beniz/root,krafczyk/root,mhuwiler/rootauto,krafczyk/root,sirinath/root,gganis/root,omazapa/root,sbinet/cxx-root,zzxuanyuan/root-compressor-dummy,jrtomps/root,zzxuanyuan/root-compressor-dummy,nilqed/root,beniz/root,veprbl/root,mhuwiler/rootauto,veprbl/root,satyarth934/root,olifre/root,sawenzel/root,arch1tect0r/root,BerserkerTroll/root,pspe/root,root-mirror/root,zzxuanyuan/root-compressor-dummy,mhuwiler/rootauto,0x0all/ROOT,Y--/root,Duraznos/root,Duraznos/root,gganis/root,perovic/root,georgtroska/root,sawenzel/root,lgiommi/root,gbitzes/root,karies/root,satyarth934/root,mattkretz/root,esakellari/my_root_for_test,simonpf/root,mattkretz/root,olifre/root,omazapa/root-old,satyarth934/root,CristinaCristescu/root,lgiommi/root,CristinaCristescu/root,omazapa/root,gbitzes/root,esakellari/root,BerserkerTroll/root,lgiommi/root,karies/root,gbitzes/root,esakellari/root,evgeny-boger/root,omazapa/root,dfunke/root,root-mirror/root,olifre/root,evgeny-boger/root,arch1tect0r/root,vukasinmilosevic/root,georgtroska/root,omazapa/root-old,omazapa/root,mkret2/root,arch1tect0r/root,sbinet/cxx-root,root-mirror/root,agarciamontoro/root,BerserkerTroll/root,CristinaCristescu/root,olifre/root,mkret2/root