@Override
        public Object apply(final String varName, final GremlinParser.VariableContext variableContext) {
            return null;
        }
Custom test implementation of {@link VariableResolver} that is not part of the standard set of implementations.
This class does nothing.
gremlin-core/src/test/java/org/apache/tinkerpop/gremlin/jsr223/VariableResolverPluginTest.java