diff --git a/app/services/tcgplayer.py b/app/services/tcgplayer.py
index 09196e6..c8599da 100644
--- a/app/services/tcgplayer.py
+++ b/app/services/tcgplayer.py
@@ -119,7 +119,7 @@ class TCGPlayerService:
             return None
         
 
-    def is_in_docker():
+    def is_in_docker(self) -> bool:
         """Check if we're running inside a Docker container"""
         try:
             with open('/proc/1/cgroup', 'r') as f: