Trying to call a class method from a protocol (Swift)

I am trying to write a fake for MFMailComposeViewController for testing so I made a protocol called MailComposeViewController and a class FakeComposeViewController that is conformed to this protocol. I also made MFMailComposeViewController conform to this protocol as well.

So in my code when I call it I am saying of type MailComposeViewController I want to have a replacement for MFMailComposeViewController.canSendMail(). If I try to replace with my protocol using: MailComposeViewController.canSendMail() I get the error Static member 'canSendMail' cannot be used on protocol metatype 'MailComposeViewController.Protocol' which makes sense. but how would I go about writing around this so I could decide to pass in a FakeComposeViewController.canSendMail() true response when testing and the real MFMailComposeViewController.canSendMail() when running?