2020-07-06: initial release
2020-07-13: added optical signal power deviation
            dependency removed with huawei_switch.include
            added huawei_entity_optical.current
2020-07-15: fixed handling of '-' sign in rx_power and tx_power    
2022-04-18: rewritten for CMK 2.0        
2022-10-23: fixed warning on upgrade "non-empty params vanished" for tx_power and rx_power