5 - Sub::WrapPackages

Attach subs as pre/post-conditions to existing subs

use Sub::WrapPackages (
    packages => [qw(User)], # wrap all User::*
    pre      => sub {
       print "called $_[0] with params ".
       join(', ', @_[1..$#_])."\n";
    },
    post     => sub {
       print "$_[0] returned $_[1]\n";
    } 
);