DB<100> sub check { die "Got extra Z: @_\n" if @_ >1 } DB<101> %h=(a=>1) => ("a", 1) DB<102> check my @v= keys %h => "" DB<103> %h=(a=>1,b=>2) => ("a", 1, "b", 2) DB<104> check my @v= keys %h Got extra Z: a b