...
Validate $.availability_status is one of the following (dictionary: DEVICE
equipment_
AVAILABILITYavailability_
STATUSESstatuses
)in case of error - return 422 ("value is not allowed in enum")
Validate $.availability_status is not equal to the current value of availability_status
in case of error - return 409 ("equipment already has {availability_status} availability_status")
...