def _add_scheme():
    """
    urllib.parse doesn't support the mongodb scheme, but it's easy
    to make it so.
    """
    lists = [
        urllib.parse.uses_relative,
        urllib.parse.uses_netloc,
        urllib.parse.uses_query,
    ]
    for l in lists:
        l.append('mongodb')
urllib.parse doesn't support the mongodb scheme, but it's easy
    to make it so.