json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "title": "Event JSON Schema to translate ORM Entity to ObjectType instance",
      "type": "object",
      "definitions": {
          "field": {
              "type": "object",
              "oneOf": [
                  {
                      "properties": {
                          "type": {
                              "type": "string",
                              "enum": [
                                  "callback"
                              ]
                          },
                          "value": {
                              "type": "string"
                          },
                          "options": {
                              "type": "object"
                          }
                      }
                  },
                  {
                      "properties": {
                          "type": {
                              "type": "string",
                              "enum": [
                                  "field",
                                  "value"
                              ]
                          },
                          "value": {
                              "type": [
                                  "string",
                                  "null",
                                  "boolean",
                                  "number"
                              ]
                          },
                          "options": {
                              "type": "object"
                          }
                      }
                  }
              ]
          }
      },
      "properties": {
          "calendar_id": {
              "$ref": "#/definitions/field"
          },
          "source": {
              "$ref": "#/definitions/field"
          },
          "source_id": {
              "$ref": "#/definitions/field"
          },
          "event_type": {
              "$ref": "#/definitions/field"
          },
          "title": {
              "$ref": "#/definitions/field"
          },
          "content": {
              "$ref": "#/definitions/field"
          },
          "start_date": {
              "$ref": "#/definitions/field"
          },
          "end_date": {
              "$ref": "#/definitions/field"
          },
          "is_recurring": {
              "$ref": "#/definitions/field"
          },
          "recurrence": {
              "$ref": "#/definitions/field"
          },
          "is_allday": {
              "$ref": "#/definitions/field"
          }
      },
      "required": [
          "source",
          "source_id",
          "start_date"
      ]
  }