diff --git a/Assets/Engine/Runtime/Engine.cs b/Assets/Engine/Runtime/Engine.cs
index 22f5468..f482fcf 100644
--- a/Assets/Engine/Runtime/Engine.cs
+++ b/Assets/Engine/Runtime/Engine.cs
@@ -98,9 +98,5 @@ namespace EscapeRoomEngine.Engine.Runtime
         }
 
         private void UpdateUI() => UpdateUIEvent?.Invoke();
-
-        // ReSharper disable once SuggestBaseTypeForParameter
-        // ReSharper disable once UnusedMember.Local
-        private bool IsNotEmpty(List<DoorModuleDescription> modules) => modules.Count > 0;
     }
 }
diff --git a/Assets/Engine/Runtime/EngineTheme.cs b/Assets/Engine/Runtime/EngineTheme.cs
index f2c6c4d..17d8a18 100644
--- a/Assets/Engine/Runtime/EngineTheme.cs
+++ b/Assets/Engine/Runtime/EngineTheme.cs
@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using EscapeRoomEngine.Engine.Runtime.Modules;
+using JetBrains.Annotations;
 using NaughtyAttributes;
 using UnityEngine;
 
@@ -37,7 +38,7 @@ namespace EscapeRoomEngine.Engine.Runtime
         [BoxGroup("Doors")] [Required]
         public DoorModuleDescription spawnDoor;
         
-        [BoxGroup("Doors")] [ValidateInput("IsNotEmpty", "At least one exit door type is required")]
+        [BoxGroup("Doors")] [ValidateInput("IsNotEmpty", "At least one exit door type is required.")]
         public List<DoorModuleDescription> exitDoorTypes;
 
         #endregion
@@ -51,5 +52,8 @@ namespace EscapeRoomEngine.Engine.Runtime
         public List<PuzzleModuleDescription> puzzleTypes;
 
         #endregion
+
+        [UsedImplicitly]
+        private bool IsNotEmpty(List<DoorModuleDescription> modules) => modules.Count > 0;
     }
 }
\ No newline at end of file