function set( text ) {
	/* eslint-disable no-invalid-this */
	var err = isValid( text );
	if ( err ) {
		throw err;
	}
	debug( 'Current value: %d.', this._text );

	this._text = text;
	debug( 'New Value: %d.', this._text );

	this.emit( CHANGE_EVENT );
}
Sets the title text.

@private
@param {string} text - text
@throws {TypeError} must be a string