package MyApp::Frontend;
use MyApp::Adaptor::Report;
sub get_report {
    MyApp::Adaptor::Report->get_report($report_id);
}

package MyApp::Adaptor::Report;
use MyApp::Backend::Report;
sub get_report {
    # some business logic such as check if report exist, etc. 
    MyApp::Backend::Report->get_report(...);
}