diff --git a/lib/File/DirWalk.pm b/lib/File/DirWalk.pm
index b766295..5c53e89 100644
--- a/lib/File/DirWalk.pm
+++ b/lib/File/DirWalk.pm
@@ -46,7 +46,7 @@ sub new {
 sub setHandler {
     my ($self,$action,$func) = @_;
 
-    if ($action !~ /onBeginWalk|onLink|onFile|onDirEnter|onDirLeave/) {
+    if (not exists $self->{$action}) {
         croak("Invalid action argument: $action");
     }