[OT] best way to determine existence of a function in a package

[Dirk Koopman]

The problem:

A user may include a local version of a package which may include one or 
  more local versions of a static function (there are no references, 
blessed or otherwise to ->can() on).

I want to detect whether or not that function is explicitly defined.

if (defined *Local::function) {
    ...
    ...
}

except that expression always returns true, which is rather a nuisance.