How do I add iam roles in aurora cluster using the service catalog?

[aryanchirania]

I want to add iam role to my aurora rds but it seems that the required variable iam_roles is not being referenced in the service catalog, whereas it is in the data storage aurora module.

In service catalog, no variable cluster_iam_roles is found. But in the data storage aurora module, it is available with defualt value as an empty list.

variable "cluster_iam_roles" {
  description = "List of IAM role ARNs to attach to the cluster. Be sure these roles exists. They will not be created here. Serverless aurora does not support attaching IAM roles."
  type        = list(string)
  default     = []
}

Service catalog: https://github.com/gruntwork-io/terraform-aws-service-catalog/blob/v0.115.4/modules/data-stores/aurora/main.tf
Aurora Module: https://github.com/gruntwork-io/terraform-aws-data-storage/blob/v0.37.1/modules/aurora/variables.tf

Now, how can I add iam role to the RDS using service catalog.