Perl doesn't really have a concept of modules. At best, it's a *file* which was required or used. I don't think you want to modify a file. I think you want to modify a package.

package MyApp::Example::Model;

####;

{
   package Example::Model;

   sub mymethod1 {
      ####;
   }

   sub mymethod2 {
      ####;
   }
}

####;

1;
[download]

Note that this will add the methods to all Example::Model objects.

There is surely a better way of doing what you really want to do.