protected function addMessage( $instance )
	{
		$message 			= \Sifo\FilterPost::getInstance()->getString( 'msgid' );
		$translator_model 	= new I18nTranslatorModel();

		// Check if this message exists in the instances parents.
		// Get selected instance inheritance.
		$instance_domains 		= $this->getConfig( 'domains', $instance );

		$instance_inheritance = array();
		if ( isset( $instance_domains['instance_inheritance'] ) )
		{
			$instance_inheritance 	=  $instance_domains['instance_inheritance'];
		}

		if ( $translator_model->getMessageInInhertitance( $message, $instance_inheritance ) > 0 )
		{
			return array( 'status' => 'KO', 'msg' => 'This message already exists in parent instance. Please, customize it.' );
		}
		elseif ( $translator_model->addMessage( $message, $instance ) )
		{
			return array( 'status' => 'OK', 'msg' => 'Message successfully saved.' );
		}

		return array( 'status' => 'KO', 'msg' => 'Failed adding message.' );
	}