feature request: set custom error class in AssertType

[ZeeD]

Hi.
I just found your project, witch is cool, and could let me avoid a lot of manual checks (I have a lot of class autogenerated by .proto files, and I wanted something to leverage the checks automatically) so, thanks for your project :)
I found the decorator @AssertType() very useful, but I was wondering if there is some way to let it know that it need to throws a custom Error, not TypeGuardError.
Moreover, as I'm not sure 100% on "how" it works, I didn't found an obvious way to wrap the decorator in a try { ... } catch { ... } block to convert the error itself.