ElementTree.iselement() returns true for the Element type

According to documentation, ElementTree.iselement() check if the argument is an element object.

But it returns true also for the Element type which has all attributes of an Element instance. The way how the Element class is defined in Python suggests that this may be intentional, but the intention was lost in the documentation.

There is also an example of dataclasses.is_dataclass() which returns true both for a dataclass type and for a dataclass instance.

So, there are two ways:

1. Fix the documentation to match the current behavior. All uses of iselement() (see #135640) should also check if the argument is a type is they need an element object.
2. Fix the implementation to check if the argument is a type. This may break the user code that uses it to check for the Element type (I don't know if it exists) but may fix bugs in the user code which expects that iselement() works as documented.

cc @scoder

Linked PRs

• gh-136482
• gh-136484

从 ElementTree.iselement() 的文档和实现开始，然后检查相关的 PR gh-136482 和 gh-136484，以及 #135640 中引用的使用处。完成的标准是确定应当修改文档所述的行为还是实现，并一致地更新相关行为或文档。