In addition to shmemem's "$self->_ss()" call, you need to update the _ss argument to be a scalar, instead of a hash, since you are calling it with a scalar "$t".:

  sub _ss {
  my ($self, $arg) = @_;

  print Dumper($arg);
}
[download]

Update: I just noticed that AnomalousMonk's post says essentially the same thing.

Actually, shmem points this out in his original post.