json_schema: {
      "additionalProperties": false,
      "items": {
          "properties": {
              "key": {
                  "title": "Key/Attribute",
                  "type": "string"
              },
              "value": {
                  "oneOf": [
                      {
                          "type": "string"
                      },
                      {
                          "type": "number"
                      },
                      {
                          "additionalProperties": false,
                          "properties": {
                              "expression_type": {
                                  "default": "stage-output-selector",
                                  "enum": [
                                      "stage-output-selector"
                                  ],
                                  "type": "string"
                              },
                              "flatten": {
                                  "type": "boolean"
                              },
                              "output": {
                                  "type": "string"
                              },
                              "stages": {
                                  "type": "string"
                              },
                              "unwrap": {
                                  "type": "boolean"
                              }
                          },
                          "required": [
                              "expression_type"
                          ],
                          "type": "object"
                      }
                  ],
                  "title": "Value"
              }
          },
          "type": "object"
      },
      "title": "Parameter Selection",
      "type": "array"
  }