Add an exception for invalid channels being referenced
Add an exception for invalid channels being referenced

shinji-s/pika,renshawbay/pika-python3,fkarb/pika-python3,benjamin9999/pika,vitaly-krugl/pika,Tarsbot/pika,jstnlef/pika,hugoxia/pika,vrtsystems/pika,zixiliuyue/pika,reddec/pika,pika/pika,Zephor5/pika,skftn/pika,knowsis/pika