Amazon web services Terraform:动态路由表路由，无法从字符串列表中检索元素

我在将路线转换为动态路线时遇到了一个问题。 默认情况下，我有3个可用性区域，每个区域都有自己的nat网关，当我尝试使用这些

nat网关时，我收到了不同类型的错误

这是
nat.tf
的输出（返回>列表[字符串]）

这是aws_route_表的块

resource "aws_route_table" "route"   {
   count                             = length(var.subnets)
   vpc_id                            = var.vpc_id

   # Route Table For IPv4
   dynamic "route" {
       for_each                      = var.route_table_ipv4
       content {
         cidr_block                  = lookup(route.value, "cidrblock", "" )
         gateway_id                  = lookup(route.value, "igw",  "" )
         instance_id                 = lookup(route.value, "instance",  "" )
         nat_gateway_id              = compact(split(",", lookup(route.value, "nat",   "")))
         vpc_endpoint_id             = lookup(route.value, "vpc_endpoint",  "" )
         local_gateway_id            = lookup(route.value, "local_gateway", "" )
         transit_gateway_id          = lookup(route.value, "transit_gateway", "" )
         network_interface_id        = lookup(route.value, "network_interface", "" )
         vpc_peering_connection_id   = lookup(route.value, "vpc_peering", "" )
       }      
   }
   tags = var.map_tags
}

以下是错误消息：

Error: Invalid value for module argument

  on main.tf line 211, in module "private_routing":
 211:    route_table_ipv4              = local.route_table_ipv4.private

The given value is not suitable for child module variable "route_table_ipv4"
defined at ../Resources/Network/Routings/variables.tf:107,1-28: element 0:
element "nat": string required.


Error: Incorrect attribute value type

  on ../Resources/Network/Routings/main.tf line 28, in resource "aws_route_table" "route":
  28:          nat_gateway_id              = compact(split(",", lookup(route.value,   "nat",   "")))

Inappropriate value for attribute "nat_gateway_id": string required.

我有什么问题？我做错了什么？
我尝试过很多选择，比如

元素（concat（查找（route.value，“nat”，“”），[“”），count.index）

元素（查找（route.value，“nat”），count.index）

compact（拆分（“，”，查找（route.value，“nat”，”）

这是主模块中的变量和声明方式

variable "route_table_ipv4"    {
   description = "The list of routes for IPv4 'CIDR' block(s)"
   type        = list(map(string))
   default     = null
}

. . . other modules . . .

route_table_ipv4 = local.route_table_ipv4.private

. . . other modules . . .


locals{
   route_table_ipv4  = {
     private = [
       {
         nat = module.gateways.nat_ids 
         cidrblock = "0.0.0.0/0"  
       }  
     ]
   }
}

我希望我的帖子也能对其他面临同样问题的人有所帮助，我希望不会太长，我尽了最大努力减少代码。期待您的评论和回答。
互联网网关没有问题
，以防您发现我犯了一个打字错误
我找到了解决方案

1-我已将变量的输入错误更改为任何
2-我使用连接到nat网关的输出，而不是在资源中，我只是拆分和计算索引

variable "route_table_ipv4"    {
   description = "The list of routes for IPv4 'CIDR' block(s)"
   type        = list(map(string))
   default     = null
}

. . . other modules . . .

route_table_ipv4 = local.route_table_ipv4.private

. . . other modules . . .


locals{
   route_table_ipv4  = {
     private = [
       {
         nat = module.gateways.nat_ids 
         cidrblock = "0.0.0.0/0"  
       }  
     ]
   }
}