def load_cassette(cassette_path):
    try:
        pc = yaml.load(open(cassette_path))
        cassette = Cassette(pc)
        return cassette
    except IOError:
        return None
def load_cassette(cassette_path):
    try:
        pc = yaml.load(open(cassette_path))
        cassette = Cassette(pc)
        return cassette
    except IOError:
        return None