lookup method

Iterable<E> lookup(
  1. Iterable<E> other,
  2. String checker(
    1. E element
    )
)

Implementation

Iterable<E> lookup(Iterable<E> other, String Function(E element) checker) {
  return where((e) {
    final a = checker(e);
    return other.map(checker).where((b) => a == b).isEmpty;
  });
}