在Jython中实现PyObject的dict查找方法：（__ findindm__ + ???）

Question

我有一个扩展PyObject的Java类，其中包含我想要用于查找的Map<String,Object>，我认为我在Jython中可以免费获得dict行为。相反，我收到错误TypeError: myclassname object is unsubscriptable。

看起来我必须至少实现PyObject.__finditem__()方法（见第654-670行）：

/**
 * Very similar to the standard Python __getitem__ method.
 * Instead of throwing a KeyError if the item isn't found,
 * this just returns null.
 *
 * Classes that wish to implement __getitem__ should
 * override this method instead (with the appropriate
 * semantics.
 *
 * @param key the key to lookup in this container
 *
 * @return the value corresponding to key or null if key is not found
 **/
public PyObject __finditem__(PyObject key) {
    throw Py.TypeError(String.format("'%.200s' object is unsubscriptable",
                                     getType().fastGetName()));
}

我该怎么做？是否有一个检查PyObject是否为String的示例？如果密钥不是字符串会发生什么？

我是否还必须覆盖__contains__？

（这与exposing a Java Map<> in Jython so that its keys are available with Python "dot" operator (attribute access)相似，但有一个相对简单的解决方案。）