Starting at the root of the document tree and moving down to the element where the event was triggered, each element is given the opportunity to handle the event.

从文档树的根开始向下移动到触发事件的元素，其中每个元素都有机会处理该事件。

To handle this, pseudo blocks certain signals when starting a wrapper, and unblocks them at the end of the wrapper.

为了处理该问题，pseudo在启动包装器时阻塞某些信号，并在包装器结束时解除阻塞。

Lines starting with the comment "handle 1st arg".

以注释“handle 1st arg”开始的行。

Lines starting with the comment "handle 2nd arg".

以注释“handle 2nd arg”开始的行。

Lines starting with the comment "now handle optional args".

以注释“now handle optional args”开始的行。