Python 3 preparation: use sum() instead of reduce(). reduce() has changed from a built-in function to something in functools in Python 3. However, since both uses were with operator.add / operator.__add__, it seemed to make more sense to use sum() instead of functools.reduce().

try:
    # Python 3+
    from http import client
except:
    # Python 2.5-2.7
    import httplib as client