не удалось устранить ошибку в magento2

Попробуйте это:

    namespace Webkul\Pos\Model\ResourceModel\Agent;


     use Magento\Framework\Model\ResourceModel\Db\Collection\AbstractCollection;
     use Magento\Framework\Data\Collection\Db\FetchStrategyInterface;
     use Magento\Framework\Data\Collection\EntityFactory;
     use Magento\Framework\DB\Adapter\AdapterInterface;
     use Magento\Framework\Event\ManagerInterface;
     use Magento\Framework\Model\ResourceModel\Db\AbstractDb;
     use Magento\Framework\DataObject\Copy\Config;
     use Psr\Log\LoggerInterface;

     class Collection extends AbstractCollection  {

         protected $_idFieldName = "id";

         protected $_fieldsetConfig;
         /**
          * @param EntityFactory $entityFactory
          * @param LoggerInterface $logger
          * @param FetchStrategyInterface $fetchStrategy
          * @param ManagerInterface $eventManager
          * @param Config $fieldsetConfig
          * @param mixed $connection
          * @param AbstractDb $resource
          */
         public function __construct(
             EntityFactory $entityFactory,
             LoggerInterface $logger,
             FetchStrategyInterface $fetchStrategy,
             ManagerInterface $eventManager,
             Config $fieldsetConfig,
             AdapterInterface $connection = null,
             AbstractDb $resource = null
         ) {
             $this->_fieldsetConfig = $fieldsetConfig;
             parent::__construct($entityFactory, $logger, $fetchStrategy, $eventManager, $connection, $resource);
         }

         protected function _construct()  {
             $this->_init("Webkul\Pos\Model\Agent", "Webkul\Pos\Model\ResourceModel\Agent");
             $this->_map["fields"]["id"] = "main_table.id";
         }




         public function setAgentData($condition, $attributeData)  {
             return $this->getConnection()->update($this->getTable("pos_agent"), $attributeData, $where = $condition);
         }

         public function groupByEmail()
         {
             $this->getSelect()->from(
                 ['email' => $this->getEntity()->getEntityTable()],
                 ['email_count' => new \Zend_Db_Expr('COUNT(email.id)')]
             )->where(
                 'email.id = e.id'
             )->group(
                 'email.email'
             );

             return $this;
         }


         public function addNameToSelect()
         {
             $fields = [];
             $agentAccount = $this->_fieldsetConfig->getFieldset('agent_account');



             foreach ($agentAccount as $code => $field) {
                 if (isset($field['name'])) {
                     $fields[$code] = $code;

                 }
             }

             $connection = $this->getConnection();
             $concatenate = [];

             $concatenate[] = 'LTRIM(RTRIM({{firstname}}))';

             $concatenate[] = 'LTRIM(RTRIM({{lastname}}))';


             $nameExpr = $connection->getConcatSql($concatenate);

             $this->addExpressionAttributeToSelect('name', $nameExpr, $fields);

             return $this;
         }

         public function getSelectCountSql()
         {
             $select = parent::getSelectCountSql();
             $select->resetJoinLeft();

             return $select;
         }


         protected function _getAllIdsSelect($limit = null, $offset = null)
         {
             $idsSelect = parent::_getAllIdsSelect($limit, $offset);
             $idsSelect->resetJoinLeft();
             return $idsSelect;
         }

     }