Get_full_list not working?

Hi, I’ve been trying to output the full list of an email marketing bean but the value that I’m getting is “1”, I tried different ways but is not working can someone help out and tell me what am i doing wrong?

$mark_search = null ;
$mrkt_email = BeanFactory::getBean(‘EmailMarketing’,$mark_search);
$mrkt_email_results = $mrkt_email->get_full_list("", “emailmarketing.campaign_id=‘4510e1c0-e522-aa0b-9d92-6172e6569323’”);

		 $body = "<html>";
		 $body = print_r($mrkt_email_results,$true);	 
		 $body .= "</html>";

In case y’all need the whole code :

class send_info_email_marketing{
		function after_login_methodtest($bean ,$event, $arguments){		
                     
             require_once $_SERVER[DOCUMENT_ROOT].'/include/SugarPHPMailer.php'; 
		
   		     $mailer=new SugarPHPMailer();
             $mailer->prepForOutbound();
       		 $mailer->setMailerForSystem();
       	     $mailer->From = "crm@ecs-support.com";
             $mailer->FromName = "CRM ADDING TO QUEUE";
       	     $mailer->IsHTML(true);
        	 $mailer->Subject = "Expecting info";
             $mark_search = null ;
			 $mrkt_email = BeanFactory::getBean('EmailMarketing',$mark_search);
			 $mrkt_email_results = $mrkt_email->get_full_list("", "emailmarketing.campaign_id='4510e1c0-e522-aa0b-9d92-6172e6569323'");
			 
			 $body = "<html>";
			 $body = print_r($mrkt_email_results,$true);	 
			 $body .= "</html>";
				
			 
             $mailer->Body = $body;    
        	 $mailer->AddAddress("dsanchez@ecs-support.com");
			 $mailer->Send();	
		}
	
	}