Use self instead of class

Models/DepartmentMapper.php

@@ -54,7 +54,7 @@ final class DepartmentMapper extends DataMapperAbstract
             'dest'   => 'organization_department_unit',
         ],
         'parent' => [
-            'mapper' => DepartmentMapper::class,
+            'mapper' => self::class,
             'dest'   => 'organization_department_parent',
         ],
     ];

Models/PositionMapper.php

@@ -51,7 +51,7 @@ final class PositionMapper extends DataMapperAbstract
      */
     protected static $belongsTo = [
         'parent'     => [
-            'mapper' => PositionMapper::class,
+            'mapper' => self::class,
             'dest'   => 'organization_position_parent',
         ],
         'department' => [

Models/UnitMapper.php

@@ -49,11 +49,11 @@ final class UnitMapper extends DataMapperAbstract
      */
     protected static $belongsTo = [
         'unit' => [
-            'mapper' => UnitMapper::class,
+            'mapper' => self::class,
             'dest'   => 'organization_uni_parent',
         ],
         'parent'  => [
-            'mapper' => UnitMapper::class,
+            'mapper' => self::class,
             'dest'   => 'organization_unit_parent',
         ],
     ];