original_string: public function get_remote_subscribers() {
          global $DB;
  
          if (is_null($this->cachesubscribers)) {
              $sql = "SELECT DISTINCT h.id, h.name AS hostname, h.wwwroot AS hosturl,
                             a.display_name AS appname
                        FROM {mnet_host} h
                        JOIN {mnet_host2service} hs ON h.id = hs.hostid
                        JOIN {mnet_service} s ON hs.serviceid = s.id
                        JOIN {mnet_application} a ON h.applicationid = a.id
                       WHERE s.name = 'mnet_enrol'
                             AND h.deleted = 0
                             AND hs.publish = 1";
              $this->cachesubscribers = $DB->get_records_sql($sql);
          }
  
          return $this->cachesubscribers;
      }
code: public function get_remote_subscribers() {
          global $DB;
  
          if (is_null($this->cachesubscribers)) {
              $sql = "SELECT DISTINCT h.id, h.name AS hostname, h.wwwroot AS hosturl,
                             a.display_name AS appname
                        FROM {mnet_host} h
                        JOIN {mnet_host2service} hs ON h.id = hs.hostid
                        JOIN {mnet_service} s ON hs.serviceid = s.id
                        JOIN {mnet_application} a ON h.applicationid = a.id
                       WHERE s.name = 'mnet_enrol'
                             AND h.deleted = 0
                             AND hs.publish = 1";
              $this->cachesubscribers = $DB->get_records_sql($sql);
          }
  
          return $this->cachesubscribers;
      }
code_tokens: public function get_remote_subscribers ( ) { global $ DB ; if ( is_null ( $ this -> cachesubscribers ) ) { $ sql = "SELECT DISTINCT h.id, h.name AS hostname, h.wwwroot AS hosturl,
                             a.display_name AS appname
                        FROM {mnet_host} h
                        JOIN {mnet_host2service} hs ON h.id = hs.hostid
                        JOIN {mnet_service} s ON hs.serviceid = s.id
                        JOIN {mnet_application} a ON h.applicationid = a.id
                       WHERE s.name = 'mnet_enrol'
                             AND h.deleted = 0
                             AND hs.publish = 1" ; $ this -> cachesubscribers = $ DB -> get_records_sql ( $ sql ) ; } return $ this -> cachesubscribers ; }
docstring: Returns a list of remote servers that can enrol their users into our courses
  
  We must publish MNet service 'mnet_enrol' for the peers to allow them to enrol
  their users into our courses.
  
  @todo once the MNet core is refactored this may be part of a parent class
  @todo the name of the service should be changed to the name of this plugin
  @return array
docstring_tokens: Returns a list of remote servers that can enrol their users into our courses