#iterable-non-iterable, map a collection to its element

In respond to discussion on user group

In implementing I was thinking: should a method marked with a qualifier, be qualifying in any other way?  In other words, if we now remove the `qualifiedBy` from the mapping, we get an ambiguous mapping method.

I can imagine that we extend our api or alternatively supply a util package containing some commonly used mappers. If a method marked with a qualifier always matches, this will limit the possibilities for such util package.