def validate_uuid_representation(dummy, value):
    """Validate the uuid representation option selected in the URI.
    """
    try:
        return _UUID_REPRESENTATIONS[value]
    except KeyError:
        raise ValueError("%s is an invalid UUID representation. "
                         "Must be one of "
                         "%s" % (value, tuple(_UUID_REPRESENTATIONS)))
Validate the uuid representation option selected in the URI.
    
stackoverflow/venv/lib/python3.6/site-packages/pymongo/common.py