sub search {
  my $wanted = shift;
  foreach my $path (@_) {
   print "Searching in '$path'\n";
   find($wanted, $path);
  }
}
# I don't care about the File::Find ... how do you pass the block to another subroutine/method? 

##</code><code>##

sub walk_tree {
  my ($self, $branch_handler, $leaf_handler) = @_;
  if ($self->isLeaf()) {
   $leaf_handler->($self->{data});
  } else {
   $branch_handler->{$self->{data}};
   foreach my $child ($self->children()) {
    $child->walk_tree($branch_handler, $leaf_handler);
   }
  }
}