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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def uuid(uuid_value=None):
 """ Returns a uuid value that is valid to use for id and identity fields. :return: unicode uuid object if using UUIDFields, uuid unicode string otherwise. """

        if uuid_value:
            if not validate_uuid(uuid_value):
                raise ValueError(
                    "uuid_value must be a valid UUID version 4 object")
        else:
            uuid_value = uuid.uuid4()

        if versions_settings.VERSIONS_USE_UUIDFIELD:
            return uuid_value
        else:
            return six.u(str(uuid_value))