Currectly, even if two `Element`s elem1 and elem2 are different objects but the tree is identical, elem1 == elem2 returns False. The only effective way to compare two `Element`s is

ElementTree.tostring(elem1) == ElementTree.tostring(elem2)

Furthermore, from 3.8 this could be not true anymore, since the order of insertion of attributes will be preserved. So if I simply wrote a tag with two identical attributes, but with different order, the trick will not work anymore.

Is it so much complicated to implement an __eq__ for `Element` that traverse its tree?

PS: some random remarks about xml.etree.ElementTree module:

1. why `fromstring` and `fromstringlist` separated functions? `fromstring` could use duck typing for the main argument, and `fromstringlist` deprecated.

2. `SubElement`: why the initial is a capital letter? It seems the constructor of a different class, while it's a factory function. I'll change it to `subElement` and deprecate `SubElement`