implements Function<F, T>, Serializable {

    private final Supplier<T> supplier;

    private SupplierFunction(Supplier<T> supplier) {
      this.supplier = checkNotNull(supplier);
    }

    @Override
    @ParametricNullness
    public T apply(@ParametricNullness F input) {
      return supplier.get();
    }

    @Override
    public boolean equals(@CheckForNull Object obj) {

      implements Function<F, T>, Serializable {

    private final Supplier<T> supplier;

    private SupplierFunction(Supplier<T> supplier) {
      this.supplier = checkNotNull(supplier);
    }

    @Override
    @ParametricNullness
    public T apply(@ParametricNullness F input) {
      return supplier.get();
    }

    @Override
    public boolean equals(@CheckForNull Object obj) {