public Function<Map<String, Object>, VariableResolver> getVariableResolverMaker() {
        return variableResolverMaker;
    }
Supplies a {@link VariableResolver} implementation to the {@link GremlinLangScriptEngine}. This {@link Customizer}
is not relevant to any other {@link GremlinScriptEngine} implementation.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/jsr223/VariableResolverCustomizer.java