Validator Field Length

Hello 

I want to set up a validator in the field when the length is greater than 10 characters, it does not allow saving that record. To achieve this I am basing myself on the following example: https://academy.creatio.com/docs/8.x/dev/development-on-creatio-platfor…

Placing it in the following way but it does not work correctly.

validators: /**SCHEMA_VALIDATORS*/{
          /* Implement a custom validator type. */
    "usr.ValidateFieldValue": {
        /* Business logic of the validator. */
        "validator": function (config) {
            return function (control) {
                return control.MaxLength !== config.invalidLength ? null: {
                    "usr.ValidateFieldValue": { message: config.message }
                };
            };
        },
        /* Validator parameters. */
        "params": [
            {
                "name": "invalidLength"
            },
            {
                "name": "message"
            }
        ],
        "async": false
    }
}/**SCHEMA_VALIDATORS*/
 
 
 

/**SCHEMA_VIEW_CONFIG_DIFF*/,
		viewModelConfigDiff: /**SCHEMA_VIEW_MODEL_CONFIG_DIFF*/[
			{
				"operation": "merge",
				"path": [
					"attributes"
				],
				"values": {
					"UsrnumerodeserieDS_Name_zb3wye6": {
						"modelConfig": {
							"path": "UsrnumerodeserieDS.Name"
						},
                       /* The property that contains the list of attribute validators. */
                        "validators": {
                            /* Custom validator. */
                            "ValidateFieldValue": {
                                /* Validator type. */
                                "type": "usr.ValidateFieldValue",
                                "params": {
                                    /* The field value that triggers the custom validator. */
                                    "invalidLength": "10",
                                    /* The tooltip that Creatio displays when the field contains the value specified in the “invalidName” property. */
                                    "message": "Invalid name."
                                }
                            }
                        }
					}
				}
			}

Also at some point I modify the code and save it but when I re-enter it does not save the changes and removes what I placed