code: public static <T> TypeChecker<List<? extends T>> tList(TypeChecker<? extends T> elementChecker) {
          return new CollectionTypeChecker<>(List.class, elementChecker);
      }
docs: Creates a recursing type checker for a {@link java.util.List}.
  
  @param elementChecker The typechecker to check the elements with
  @return a typechecker for a List containing elements passing the specified type checker