diff --git a/mapadroid/madmin/endpoints/api/apks/MadApkEndpoint.py b/mapadroid/madmin/endpoints/api/apks/MadApkEndpoint.py
index e85ef061e..9740d5f1b 100644
--- a/mapadroid/madmin/endpoints/api/apks/MadApkEndpoint.py
+++ b/mapadroid/madmin/endpoints/api/apks/MadApkEndpoint.py
@@ -38,7 +38,7 @@ async def get(self):
             except KeyError:
                 return await self._json_response(data=data[apk_type])
 
-    def allowed_file(filename):
+    def allowed_file(self, filename):
         ALLOWED_EXTENSIONS = set(['apk', 'apkm', 'zip'])
         return '.' in filename and filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS