assertThat(typeArgs).asList().hasSize(1);
    TypeVariable<?> captured = (TypeVariable<?>) typeArgs[0];
    assertThat(captured.getBounds()).asList().contains(Number.class);
    assertThat(captured.getBounds())
        .asList()
        .containsNoneOf(Object.class, new TypeToken<Iterable<Number>>() {}.getType());

  final TypeToken<? super T> getGenericSuperclass() {
    if (runtimeType instanceof TypeVariable) {
      // First bound is always the super class, if one exists.
      return boundAsSuperclass(((TypeVariable<?>) runtimeType).getBounds()[0]);
    }
    if (runtimeType instanceof WildcardType) {
      // wildcard has one and only one upper bound.
      return boundAsSuperclass(((WildcardType) runtimeType).getUpperBounds()[0]);
    }

    assertThat(typeArgs).asList().hasSize(1);
    TypeVariable<?> captured = (TypeVariable<?>) typeArgs[0];
    assertThat(captured.getBounds()).asList().contains(Number.class);
    assertThat(captured.getBounds())
        .asList()
        .containsNoneOf(Object.class, new TypeToken<Iterable<Number>>() {}.getType());