permute method

@override List<E> permute(List<E> instance)

Generates another instance with some deterministic function.

The only exception is Kind.forNull (because it has no other instances).

Implementation

@override
List<E> permute(List<E> instance) {
  if (instance.isEmpty) {
    return [elementKind.newInstance()];
  }
  return instance.map(elementKind.permute).toList();
}