shorten the 'where(lamba (using))` idiom

[theodox]

there's a lot of examples that look like this:

no_uvs = Meshes().where_not(lambda p: any(using(p).get(UVPointCount)))

Which is fine - but it's common enough that it would be nice to get rid of the boilerplate.

What's a nice elegant way to elide lambda p: using(p).get(XXX)....?