Python 2 let you put a u in front of a string literal to make it unicode. Python 3 made it a syntax error at first. Python 3.3 restored it so people could write

Python 2 let you put a u in front of a string literal to make it unicode. Python 3 made it a syntax error at first. Python 3.3 restored it so people could write code compatible with 2 and 3 without importing unicode_literals.