怎么获取单选按钮或进度条状态或值？

**描述问题bug**
怎么获取单选按钮、多选按钮、进度条相关状态或值？属性中没有checked、checkable、selected属性，怎么去获取它的相关值？截图见下方

**预期效果**
预期想有获取相关状态的关键字，或函数

**相关截图**
属性截图

**python 版本:** `python3.6.7 `
python3.6.7 64位

**poco 版本:** `1.0.69`
> pocoui版本:1.0.76

The issue names no source file, test, or entry point. Start by tracing how Poco and pocoui expose UI properties for radio buttons, checkboxes, and progress bars, then reproduce the reported controls with the stated Python and Poco versions. Done means the relevant state or value can be retrieved through a documented keyword or function.

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