@Test
    public void testReturnTypes() {
        assertEquals("hello", __.__("HELLO").toLower(Scope.local).next());
        assertArrayEquals(new String[]{"test"}, ((List<?>) __.__(Collections.singletonList("TEST")).toLower(Scope.local).next()).toArray());
        assertArrayEquals(new String[]{"test"}, ((List<?>) __.__(new HashSet<>(Collections.singletonList("TEST"))).toLower(Scope.local).next()).toArray());
        assertArrayEquals(new String[]{"hello", "test", "no.123", null, ""},
                ((List<?>) __.__(Arrays.asList("hElLo", "TEST", "NO.123", null, "")).toLower(Scope.local).next()).toArray());
    }
@author Yang Xia (http://github.com/xiazcy)
gremlin-core/src/test/java/org/apache/tinkerpop/gremlin/process/traversal/step/map/ToLowerLocalStepTest.java