MySql fetch data error

Hey guys !
Got a problem right now, I can't fetch data from my model, each operation results to an error : "Call to a member function getResult() on bool"

Error :

PHP Code:

SYSTEMPATH/Model.php at line 198

191        if ($this->tempUseSoftDeletes)
192        {
193            $builder->where($this->table . '.' . $this->deletedField, null);
194        }
195 
196        return $builder->limit($limit, $offset)
197            ->get()
198            ->getResult($this->tempReturnType);
199    } 


Here's my code :

PHP Code:

<?php

namespace App\Models;

use CodeIgniter\Model;

class PeriodTypeModel extends Model 
{
 protected $table = "period_type";
    protected $primaryKey = "id";
    protected $useAutoIncrement = true;
    protected $returnType = "array";
    protected $useSoftDeletes = true;
    protected $allowedFields = ["name", "color"];
    protected $useTimestamps = false;
    protected $createdField = "created_at";
    protected $updatedField = "updated_at";
    protected $deletedField = "deleted_at";
    protected $validationRules = [];
    protected $validationMessages = [];
    protected $skipValidation = false;

    public function create_period_type($name, $color)
    {
    $data = 
    [
    "name" => $name,
    "color" => $color
    ];
        $this->insert($data);
    }
} 


PHP Code:

$periodTypeModel = model("PeriodTypeModel");
        $data = $periodTypeModel->findAll(); 


It seems like line 197 isn't returning a result object but a boolean, how can I resolve it ? Is it a problem from me or CodeIgniter ? 
I'm using latest version of CodeIgniter (v4.1.3), php 7.3 and MySql 8.0.23.

do like bellow
$periodTypeModel->where()->get()->getResultArray();

Enlightenment  Is  Freedom

Oh well, that's working perfectly, was following https://codeigniter4.github.io/userguide...nding-data but seems like we can't do this way ? Anyway now that's fixed ! Thanksss !