package App::Controller::Setup;
use Mojo::Base 'Mojolicious::Controller';
use Mojo::Base 'App::Sys::Example';

...

sub myaction (
	my $self = shift;

...

	my $result = App::Sys::Example->myfunction('hello world');






#App/Sys/Example.pm:
use 'App::Sys::Example';

sub myfunction () {

	my $value = $_;

...

}

return 1;