Cloudformation ECR Repository syntax

Early decision by AWS to make the LifecyclePolicy a Type: String instead of Json means there is no easy way to use native yaml in a cloudformation template to format the rules.
Solution:

  ECRRepository2:
    Type: AWS::ECR::Repository
    Properties:
      ImageScanningConfiguration:
        ScanOnPush: True
      ImageTagMutability: MUTABLE
      LifecyclePolicy:
            #poor aws design..lifecycle policy text is a string, not type: json
          LifecyclePolicyText: |
            {"rules": [
                {"rulePriority": 1,
                "description":  "Remove older versions",
                "selection": {
                    "tagStatus": "any",
                    "countType": "imageCountMoreThan",
                    "countNumber": 10 },
                  "action": {
                    "type": "expire" }
            }]}