Duck typing is the best if fully embraced. But it also means you have to worry just a little bit about clean failures once the project grows a little. I like this better than type checking relentlessly.
It also means that your test suite or doctests or whatever should throw some unexpected types around now and again to check how it handles ducks and chickens and such :)
All I'm hearing is complaining. It's open source. Fix mate then so it does what you want.