无服务器框架 - 尝试填充非字符串值错误

如何解决无服务器框架 - 尝试填充非字符串值错误

我有许多 SNS 主题的 serverless.yaml，我需要从跨账户和区域的名称构建 ARN，所以我带有自定义前缀

custom:
  snsTopicPrefix:
    Fn::Join:
      - ":"
      - - "arn:aws:sns"
        - !Ref "AWS::Region"
        - !Ref "AWS::AccountId"

  topic01: Topic-01-test

functions:    
  from-SNS:
    handler: src/fromSNS/handler.fromSNS
    events:
      - sns:
          arn: ${self:custom.snsTopicPrefix}:${self:custom.topic01}
          topicName: ${self:custom.topic01}

但是，当我部署它时，我无法传递错误 Trying to populate non string value into a string for variable ${self:custom.snsTopicPrefix}. Please make sure the value of the property is a string.