diff --git a/src/mcp_synology_container/modules/compose.py b/src/mcp_synology_container/modules/compose.py
index d627ce4..16c0449 100644
--- a/src/mcp_synology_container/modules/compose.py
+++ b/src/mcp_synology_container/modules/compose.py
@@ -272,7 +272,9 @@ def register_compose(mcp: FastMCP, config: AppConfig, client: DsmClient) -> None
             new_entry = f"{var_name}={var_value}"
             updated = False
             for i, entry in enumerate(env_list):
-                if isinstance(entry, str) and entry.startswith(f"{var_name}=") or entry == var_name:
+                if isinstance(entry, str) and (
+                    entry.startswith(f"{var_name}=") or entry == var_name
+                ):
                     env_list[i] = new_entry
                     updated = True
                     break