ios - Cannot Invoke setMetadataObjectsDelegate with an argument list of type (CustomVC, queue:dispatch_queue_t!) -

it doesn't arguments i'm putting setmetadataobjectsdelegate. here's code, i've put in uiviewcontroller subclass under viewdidload

capturemetadataoutput.metadataobjectsdelegate capturemetadataoutput.setmetadataobjectsdelegate(self, queue:  dispatch_get_main_queue()) capturemetadataoutput.metadataobjecttypes = [avmetadataobjecttypeqrcode] capturesession?.addoutput(capturemetadataoutput) 

my suspicion problem more use of 'self' dispatch_get_main_queue(), don't know. code seems it's worked other people.