coerce 'MyApp::To' 
    => from 'Str' 
    => via { MyApp::To->new(text => $_) };
coerce 'MyApp::From' 
    => from 'Str' 
    => via { MyApp::From->new(text => $_) };
coerce 'MyApp::Heading' 
    => from 'Str' 
    => via { MyApp::Heading->new(text => $_) };
coerce 'MyApp::Body' 
    => from 'Str' 
    => via { MyApp::Body->new(text => $_) };