toString() {
        const ThisModel = this.getClass();
        const className = ThisModel.modelName;
        const fieldNames = Object.keys(ThisModel.fields);
        const fields = fieldNames
            .map((fieldName) => {
                const field = ThisModel.fields[fieldName];
                if (field instanceof ManyToMany) {
                    const ids = this[fieldName]
                        .toModelArray()
                        .map((model) => model.getId());
                    return `${fieldName}: [${ids.join(", ")}]`;
                }
                const val = this._fields[fieldName];
                return `${fieldName}: ${val}`;
            })
            .join(", ");
        return `${className}: {${fields}}`;
    }
Returns a string representation of the {@link Model} instance.

@return {string} A string representation of this {@link Model} instance.