set_value() is working but set_select() not working

Code:

<select name="doc_type_id" class="form-select">

                    <option value="">Select</option>



                    <?php foreach ($doc_types as $doc): ?>

                        <option value="<?= $doc['id']; ?>" <?= set_select('doc_type_id', $doc['id']) ?>> <?= $doc['name']; ?>

                        </option>

                    <?php endforeach; ?>

                </select>

Code:

<?php



namespace App\Models;



use CodeIgniter\Model;



class DocumentsModel extends Model

{



    protected $table = 'documents';



    protected $returnType = '\App\Entities\DocumentsEntity';



    protected $allowedFields = ['no', 'expiry_date', 'doc_type_id', 'doc_file'];



    // Dates

    protected $useTimestamps = true;



    protected $validationRules = [



        'no' => 'required',

        'expiry_date' => 'required',

        'doc_type_id' => 'required',

        'doc_file' => 'uploaded[doc_file]|ext_in[doc_file,png,jpg,gif]|max_size[doc_file,800]',



    ];

    protected $validationMessages = [



        'no' => [



            'required' => 'Please enter valid doc no',



        ],



        'expiry_date' => [



            'required' => 'Please select a valid date',



        ],





        'doc_type_id' => [



            'required' => 'Please select a document type.',



        ],





        'doc_file' => [



            'uploaded' => 'Please upload a valid file.',

            'ext_in' => 'Invalid file type',

            'max_size' => 'File should be less than 800kb.'



        ],





    ];





    public function getDocs()

    {



        $this->builder()

            ->select('a.id as doc_id, a.no as doc_no, a.expiry_date as doc_expiry, b.name as doc_type, a.doc_file as doc_file, a.updated_at as updated_at')

            ->from('documents as a')

            ->join('documents_type as b', 'a.doc_type_id = b.id', 'INNER')

            ->groupBy('a.id');



        return $this;





    }





}

Code:

public function createDocument()

    {



        if ($this->request->getPost()) {

            $model = new DocumentsModel;

            $documents = new DocumentsEntity;



            $documents->no = $this->request->getPost('no');

            $documents->doc_type_id = $this->request->getPost('doc_type_id');

            $documents->expiry_date = $this->request->getPost('expiry_date');

            $documents->doc_file = $this->request->getFile('doc_file');



            if ($model->save($documents)) {



                return redirect()->back()

                    ->with('success', "Document added success")

                    ->withInput();

            } else {



                return redirect()->back()

                    ->with('warning', 'Please fix following errors!')

                    ->with('errors', $model->errors())

                    ->withInput();



                // return redirect()->back()

                //    ->with('success', "Document added success")

                //    ->withInput();

            }





        }



        $doc_types = new DocumentTypesModel;

        $doc_types = $doc_types->findAll();



        return view('employees/documents/create', [

            'doc_types' => $doc_types,

        ]);

    }