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

Beginne mit der Dokumentation und Implementierung von ElementTree.iselement(), untersuche anschließend die verknüpften PRs gh-136482 und gh-136484 sowie die in #135640 referenzierten Verwendungen. Als abgeschlossen gilt die Klärung, ob das dokumentierte Verhalten oder die Implementierung geändert werden sollte, sowie die konsistente Aktualisierung des entsprechenden Verhaltens oder der Dokumentation.