Fix bug. Since chrid is forced to be int, it can't be 'None'.
Fix bug. Since chrid is forced to be int, it can't be 'None'.

taoliu/MACS,vd4mmind/MACS,daler/MACS,taoliu/MACS,vd4mmind/MACS,vd4mmind/MACS,daler/MACS,taoliu/MACS,daler/MACS