import zipfile


def extract_zipfile(source_zip):
    """
    unzips your new zip file into a temporary directory to work in
    :param source_zip: a .zip file
    :return: None. should create a temp dir in the PWD then put the .zip contents in it
    """
    # unzip the .zip
    zip_ref = zipfile.ZipFile(source_zip, 'r')
    zip_ref.extractall('./temp')
    return zip_ref