def nice():
    """
    Returns a randomly generated uuid v4 compliant slug which conforms to a set
    of "nice" properties, at the cost of some entropy. Currently this means one
    extra fixed bit (the first bit of the uuid is set to 0) which guarantees the
    slug will begin with [A-Za-f]. For example such slugs don't require special
    handling when used as command line parameters (whereas non-nice slugs may
    start with `-` which can confuse command line tools).

    Potentially other "nice" properties may be added in future to further
    restrict the range of potential uuids that may be generated.
    """
    rawBytes = bytearray(uuid.uuid4().bytes)
    rawBytes[0] = rawBytes[0] & 0x7f  # Ensure slug starts with [A-Za-f]
    return _convert_bytes_to_slug(rawBytes)