extractAttributes( modelClass, data ) {
		const { typeKey } = this;
		const attributes = this._super( ...arguments );
		if ( data && hasOwnProperty.call( data, typeKey ) ) {
			attributes[ typeKey ] = data[ typeKey ];
		}

		return attributes;
	}
Fix removal of the `typeKey` property
@param {Model} modelClass
@param {Object} [data]
@returns {Object}