Counter-intuitive naming

[sjbrown]

Hi, sorry for the brevity - just something I noticed that irked me:

error_message = is_valid_method(self.__model__, resource)

I would expect a functioned named is_valid_method(...) to return True if the endpoint usage was valid. Instead, if it returns an error_message (which evaluates to True), that indicates it wasn't a valid usage.

Maybe a name like validation_errors or validate_method would be more intuitive.