def create_item_version(item):
    """Item version based on hashlib.sha1 algorithm"""
    if not item.version_fields:
        return
    _hash = hashlib.sha1()
    for attrname in item.version_fields:
        _hash.update(repr(item.get(attrname)).encode('utf-8'))
    return _hash.digest()
Item version based on hashlib.sha1 algorithm
slybot/slybot/item.py