Turning a signature-changing decorator into a signature-preserving one

[Gustavo Narea]

Hello, everybody.

I have this signature-changing decorator
<http://paste.chrisarndt.de/paste/15aac02a90094a41a13a1b9b85a14dd6>
which I
want to turn into a signature-preserving one. Here's my try
<http://paste.chrisarndt.de/paste/d0f835c00f824437bf4a0898f8020fc8>,
but I get
this error:
http://paste.chrisarndt.de/paste/33e06be6e6d74e49b05c45534dfcc9fe?wrap=no

What am I doing wrong? I think it looks like this example:
http://pypi.python.org/pypi/decorator#async

Thanks in advance.

  - Gustavo.

PS: functols.wrap is not an option because my code has to work with
Python 2.4+.