@Override
    public String toString() {
        return key;
    }
@Test
    public void testToString() {
        NamespaceBundle bundle0 = factory.getBundle(NamespaceName.get("pulsar/use/ns1"),
                Range.range(0l, BoundType.CLOSED, 0x10000000L, BoundType.OPEN));
        assertEquals(bundle0.toString(), "pulsar/use/ns1/0x00000000_0x10000000");
        bundle0 = factory.getBundle(NamespaceName.get("pulsar/use/ns1"),
                Range.range(0x10000000l, BoundType.CLOSED, NamespaceBundles.FULL_UPPER_BOUND, BoundType.CLOSED));
        assertEquals(bundle0.toString(), "pulsar/use/ns1/0x10000000_0xffffffff");
    }