Decompress any archive in Python

gistfile1.py

# pip
from pip.download import unpack_file_url

class _DummyLink(object):
    """ A dummy class for staying consistent with pip's API in certain places
    below.
    """
    def __init__(self, url):
        self.url = url

def decompress(archive, dir_name):
    """ Decompresses an archive into a directory, the directory must already exist.
    """
    unpack_file_url(_DummyLink('file:' + archive), dir_name)