Variable type map: limit to the list of values

my search skills are taking a leave today.

Problem statement:
i would like to check if a variable is in the list of allowed values.

not working code:

variable "vms" {
  type = map(object({
    instance_type     = string
    tag_productfamily = list(string)
  validation {
  condition     = length([for tag in values(var.vms)[*].tag_productfamily : tag if !contains(["AAA", "BB"], tag)]) <= 0
  error_message = "Only AA and BB are allowed values for tag."

Appreciate your help.

Today i found my search skill: terraform - validating map of objects - DevOps Stack Exchange