Python regex matching Unicode properties

Perl and some other current regex engines support Unicode properties, such as the category, in a regex. E.g. in Perl you can use p{Ll} to match an arbitrary lower-case letter, or p{Zs} for any space separator. I don’t see support for this in either the 2.x nor 3.x lines of Python (with due regrets). Is anybody aware of a good strategy to get a similar effect? Homegrown solutions are welcome.

How can I convert surrogate pairs to normal string in Python?

This is a follow-up to Converting to Emoji. In that question, the OP had a json.dumps()-encoded file with an emoji represented as a surrogate pair – ud83dude4f. S/he was having problems reading the file and translating the emoji correctly, and the correct answer was to json.loads() each line from the file, and the json module would handle the conversion from surrogate pair back to (I’m assuming UTF8-encoded) emoji.