diff --git a/app/Actions/CourseWithSections.php b/app/Actions/CourseWithSections.php
index 1b8790e..8d6dd80 100644
--- a/app/Actions/CourseWithSections.php
+++ b/app/Actions/CourseWithSections.php
@@ -2,11 +2,9 @@
 namespace App\Actions;
 
 use App\Http\Resources\CourseResource;
-use App\Models\User;
 use App\Models\Course;
 use App\Models\Section;
 use Illuminate\Support\Facades\Cache;
-use Illuminate\Pagination\LengthAwarePaginator;
 use Illuminate\Support\Collection;
 
 class CourseWithSections
diff --git a/app/Exceptions/Handler.php b/app/Exceptions/Handler.php
index dedc91c..62e9ff8 100644
--- a/app/Exceptions/Handler.php
+++ b/app/Exceptions/Handler.php
@@ -15,7 +15,7 @@ class Handler extends ExceptionHandler
     /**
      * A list of the exception types that are not reported.
      *
-     * @var array<int, string>
+     * @var array<int, string|null>
      */
     protected $dontReport = [
         //
diff --git a/app/Http/Resources/UserResource.php b/app/Http/Resources/UserResource.php
index 5f07a37..5054cfa 100644
--- a/app/Http/Resources/UserResource.php
+++ b/app/Http/Resources/UserResource.php
@@ -24,8 +24,8 @@ public function toArray(Request $request): array
             'email' => $this->email,
             'avatar' => $this->avatar,
             'email_verified_at' => $this->email_verified_at?->format('Y-m-d H:i:s'),
-            'created_at' => $this->created_at?->format('Y-m-d H:i:s'),
-            'updated_at' => $this->updated_at?->format('Y-m-d H:i:s'),
+            'created_at' => $this->created_at->format('Y-m-d H:i:s'),
+            'updated_at' => $this->updated_at->format('Y-m-d H:i:s'),
             'deleted_at' => $this->deleted_at?->format('Y-m-d H:i:s'),
             'roles' => RoleResource::collection($this->whenLoaded('roles')),
             'results' => ResultResource::collection($this->whenLoaded('results')),
diff --git a/app/Models/Course.php b/app/Models/Course.php
index c879867..d0b87b2 100644
--- a/app/Models/Course.php
+++ b/app/Models/Course.php
@@ -3,12 +3,14 @@
 namespace App\Models;
 
 use App\Models\Exam;
+use Illuminate\Support\Carbon;
 use App\Models\Traits\Fileable;
-use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Auth;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\SoftDeletes;
-use Illuminate\Support\Facades\Auth;
-use Illuminate\Support\Facades\DB;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
 
 /**
  * @property int $id
diff --git a/app/Models/Exam.php b/app/Models/Exam.php
index ef70f84..374a8e1 100644
--- a/app/Models/Exam.php
+++ b/app/Models/Exam.php
@@ -7,7 +7,9 @@
 use App\Models\Result;
 use App\Models\Subject;
 use App\Models\Question;
+use Illuminate\Support\Carbon;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\SoftDeletes;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 
diff --git a/app/Models/File.php b/app/Models/File.php
index 0377ede..f257895 100644
--- a/app/Models/File.php
+++ b/app/Models/File.php
@@ -3,12 +3,14 @@
 namespace App\Models;
 
 use App\Models\User;
-use App\Models\Traits\HashesId;
 use App\Jobs\ResizedImage;
-use App\Models\Traits\FileStorage;
+use Illuminate\Support\Carbon;
+use App\Models\Traits\HashesId;
 use App\Observers\FileObserver;
+use App\Models\Traits\FileStorage;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Support\Facades\Storage;
+use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\SoftDeletes;
 
 /**
diff --git a/app/Models/Lesson.php b/app/Models/Lesson.php
index 7190048..8d48b7a 100644
--- a/app/Models/Lesson.php
+++ b/app/Models/Lesson.php
@@ -4,9 +4,11 @@
 
 use Auth;
 use App\Models\File;
+use Illuminate\Support\Carbon;
 use App\Models\Traits\Fileable;
 use App\Models\Traits\Topicable;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\SoftDeletes;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 
@@ -125,7 +127,7 @@ public function setStatusAttribute($value)
         if ($key) {
             $this->attributes['status'] = $value;
         } else {
-            $this->attributes['status'] = self::$status[$value];
+            $this->attributes['status'] = self::$statuses[$value];
         }
     }
 
diff --git a/app/Models/Question.php b/app/Models/Question.php
index b0d6e96..94531d3 100644
--- a/app/Models/Question.php
+++ b/app/Models/Question.php
@@ -4,7 +4,9 @@
 
 use App\Models\Exam;
 use App\Models\Topic;
+use Illuminate\Support\Carbon;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\SoftDeletes;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 
diff --git a/app/Models/Result.php b/app/Models/Result.php
index ebb11e7..ec90070 100644
--- a/app/Models/Result.php
+++ b/app/Models/Result.php
@@ -4,7 +4,9 @@
 
 use App\Models\Exam;
 use App\Models\User;
+use Illuminate\Support\Carbon;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 
 /**
@@ -50,7 +52,7 @@ public static function calculateMark($answer)
             foreach ($answer as $resultKey => $resultValue) {
                 $question = Question::where('id', $resultKey)->first();
                 if (!empty($question)) {
-                    foreach ($question->answer as $key => $value) {
+                    foreach ($question->answers as $key => $value) {
                         if ($resultValue == $value) {
                             $count = $count + $question->mark;
                         }
diff --git a/app/Models/Role.php b/app/Models/Role.php
index fecf019..979fc6d 100644
--- a/app/Models/Role.php
+++ b/app/Models/Role.php
@@ -1,6 +1,7 @@
 <?php
 namespace App\Models;
 
+use Illuminate\Support\Carbon;
 use Illuminate\Support\Collection;
 use Spatie\Permission\Models\Role as ModelsRole;
 
diff --git a/app/Models/Section.php b/app/Models/Section.php
index 242bd36..0a9dce6 100644
--- a/app/Models/Section.php
+++ b/app/Models/Section.php
@@ -2,7 +2,9 @@
 
 namespace App\Models;
 
+use Illuminate\Support\Carbon;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 
 /**
diff --git a/app/Models/Sectionable.php b/app/Models/Sectionable.php
index 36a8e3a..7cae383 100644
--- a/app/Models/Sectionable.php
+++ b/app/Models/Sectionable.php
@@ -2,7 +2,9 @@
 
 namespace App\Models;
 
+use Illuminate\Support\Carbon;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 
 /**
diff --git a/app/Models/Subject.php b/app/Models/Subject.php
index b2e163e..23566f3 100644
--- a/app/Models/Subject.php
+++ b/app/Models/Subject.php
@@ -3,7 +3,9 @@
 namespace App\Models;
 
 use App\Models\Exam;
+use Illuminate\Support\Carbon;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 
 /**
diff --git a/app/Models/Topic.php b/app/Models/Topic.php
index 96ba060..be60b5c 100644
--- a/app/Models/Topic.php
+++ b/app/Models/Topic.php
@@ -2,8 +2,11 @@
 
 namespace App\Models;
 
+use Carbon\Carbon;
 use App\Models\Exam;
+use App\Models\Course;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 
 /**
diff --git a/app/Models/User.php b/app/Models/User.php
index 29e3cda..1c05466 100644
--- a/app/Models/User.php
+++ b/app/Models/User.php
@@ -2,11 +2,13 @@
 
 namespace App\Models;
 
+use Carbon\Carbon;
 use App\Models\Result;
-use Laravel\Sanctum\HasApiTokens;
 use App\Pivots\StudentCasting;
+use Laravel\Sanctum\HasApiTokens;
 use Spatie\Permission\Traits\HasRoles;
 use Illuminate\Notifications\Notifiable;
+use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\SoftDeletes;
 use Illuminate\Contracts\Auth\MustVerifyEmail;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
@@ -26,7 +28,7 @@
  * @property string $fullName
  * @property Carbon $created_at
  * @property Carbon $updated_at
- * @property Carbon $deleted_at
+ * @property ?Carbon $deleted_at
  * @property Collection<Role> $roles
  * @property Collection<Result> $results
  * @property Collection<Course> $instructCourses