Verify that value is True, False, 0, or 1

def assert_bool(dist, attr, value):
    """Verify that value is True, False, 0, or 1"""
    if bool(value) != value:
        tmpl = "{attr!r} must be a boolean value (got {value!r})"
        raise DistutilsSetupError(tmpl.format(attr=attr, value=value))