json_schema: {
      "title": "featureExpressionInfo",
      "type": "object",
      "$schema": "http://json-schema.org/draft-04/schema",
      "description": "An object that defines an expression for per-feature elevation.",
      "properties": {
          "expression": {
              "type": "string",
              "description": "An [Arcade expression](https://developers.arcgis.com/arcade/) evaluating to a number.",
              "minLength": 1
          },
          "title": {
              "type": "string",
              "description": "Title of the expression.",
              "minLength": 1
          }
      },
      "required": [
          "expression"
      ],
      "additionalProperties": false,
      "esriDocumentation": {
          "examples": [
              {
                  "title": "Zero expression",
                  "description": "Do not use geometry.z values",
                  "code": {
                      "featureExpressionInfo": {
                          "expression": "0"
                      }
                  }
              },
              {
                  "title": "Expression with field name",
                  "description": "Elevation from field value without geometry.z",
                  "code": {
                      "featureExpressionInfo": {
                          "expression": "$feature.ELEVATION_FOOT"
                      }
                  }
              }
          ]
      }
  }