This operation sets the user label of an object.

If there has been a change in the value of the userLabel attribute, then the EMS forwards an AVC notification.

Once an object is created, the userLabel may only be changed by an NMS through this operation.

Operation Exceptions:
1. NOT_IMPLEMENTED - If EMS does not support this operation.
2. INTERNAL_ERROR - Raised in case of non-specific EMS internal failure.
3. INVALID_INPUT - Raised when objectName is incorrectly formed.
4. ENTITY_NOT_FOUND - Raised when objectName references object which does not exist.
5. UNABLE_TO_COMPLY - Raised when the userLabel can not be set for the specified object.
6. NE_COMM_LOSS - Raised when communication to managed element is lost.
7. USERLABEL_IN_USE - Raised when the userLabel uniqueness constraint is not met.
