How to use the apicurio-data-models.SimplifiedPropertyType.fromPropertySchema function in apicurio-data-models

public changeRequired(newValue: string): void {
        this.model().required = newValue === "required";
        let nt: SimplifiedPropertyType = SimplifiedPropertyType.fromPropertySchema(this.item);
        nt.required = this.model().required;
        let command: ICommand = CommandFactory.createChangePropertyTypeCommand(this.item, nt);
        this.commandService.emit(command);
    }

protected updateModel(): void {
        this._model = SimplifiedPropertyType.fromPropertySchema(this.item);
    }

public displayType(): SimplifiedParameterType {
        return SimplifiedPropertyType.fromPropertySchema(this.item);
    }