Provide readable error message when attempting to delete collection containing invalid media_objects
Provide readable error message when attempting to delete collection containing invalid media_objects

avalonmediasystem/avalon,uvalib/avalon,ualbertalib/avalon,nulib/avalon,uvalib/avalon,uvalib/avalon,ualbertalib/avalon,ualbertalib/avalon,avalonmediasystem/avalon,avalonmediasystem/avalon,nulib/avalon,uvalib/avalon,nulib/avalon,nulib/avalon,ualbertalib/avalon,avalonmediasystem/avalon