Terraform使用count with list inside list变量吗？

variable "instances" {
  type = list(object({
    name     = string
    subnets  = list(string)
    security_groups = list(string)
  }))
  default = [
    {
      name     = "instance1"
      subnets  = ["subnet1", "subnet2"]
      security_groups = ["sg1"]
    },
    {
      name     = "instance2"
      subnets  = ["subnet3"]
      security_groups = ["sg2", "sg3"]
    }
  ]
}

resource "aws_instance" "example" {
  count = length(var.instances)

  ami           = "ami-0c94855ba95c71c99"
  instance_type = "t2.micro"
  subnet_id     = var.instances[count.index].subnets[count.index]
  security_group_ids = var.instances[count.index].security_groups
}