private void tryCastMapNullableArgument(GremlinParser.GenericMapNullableArgumentContext ctx) {
        if (ctx.genericMapNullableLiteral() != null
                && ctx.genericMapNullableLiteral().nullLiteral() != null) {
            sb.append("(Map) null");
        } else {
            visit(ctx);
        }
    }
Special handling for inject with second `null` argument like g.inject(1, null)
inject() ends up being ambiguous with groovy's jdk extension of inject(Object initialValue, Closure closure)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/language/translator/GroovyTranslateVisitor.java