如何构造terraform代码，在创建后获得Lambda ARN？

resource "aws_lambda_function" "my_lambda" {
  function_name = "my-lambda-function"
  runtime       = "python3.8"
  handler       = "main.lambda_handler"
  filename      = "lambda_function.zip"
  role          = aws_iam_role.my_lambda_role.arn
  timeout       = 300
  memory_size   = 128
  environment {
    variables = {
      ENV_VAR = "example"
    }
  }
}

resource "aws_iam_role" "my_lambda_role" {
  name = "my-lambda-role"

  assume_role_policy = <<EOF
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {
        "Service": "lambda.amazonaws.com"
      },
      "Action": "sts:AssumeRole"
    }
  ]
}
EOF
}

terraform init
terraform apply

output "lambda_arn" {
  value = aws_lambda_function.my_lambda.arn
}