pub fn call_for_targets<'a, Iter, I, T, E, F>(
targets: Iter,
f: F,
) -> Result<Result<(), E>, TargetInvalid>where
Iter: ExactSizeIterator<Item = &'a I>,
I: AsRef<str> + 'a,
T: TargetTrait<'a> + 'a,
F: Fn(&T) -> Result<(), E>,