stopped shout when set not defined

modules/Bio/EnsEMBL/DBSQL/MiscFeatureAdaptor.pm

@@ -90,9 +90,12 @@ sub fetch_all_by_Slice_and_set_code {
   my $max_len = 0;
   foreach my $set_code (@_) {
     my $set = $msa->fetch_by_code($set_code);
-    $max_len = $set->longest_feature() if($set->longest_feature > $max_len);
-    if(!$set) { warning("No misc_set with code [$set_code] exists") }
-    else { push @sets, $set->dbID; }
+    if($set) {
+      $max_len = $set->longest_feature if $set->longest_feature > $max_len;
+      push @sets, $set->dbID;
+    } else { 
+      warning("No misc_set with code [$set_code] exists");
+    }
   }
   my $constraint;
   if( @sets > 1 ) {