diff --git a/utilities/earthly-cache-watcher/main.py b/utilities/earthly-cache-watcher/main.py
index 66485d612..967189641 100644
--- a/utilities/earthly-cache-watcher/main.py
+++ b/utilities/earthly-cache-watcher/main.py
@@ -64,8 +64,8 @@ def __init__(self, interval: int):
         self.layer_growth_index: dict[str, int] = {}
         self.layer_index: dict[str, int] = {}
         self.file_index: dict[str, int] = {}
-        self.triggered_layers: Set[str] = set()
-        self.triggered_growth_layers: Set[str] = set()
+        self.triggered_layers: set[str] = set()
+        self.triggered_growth_layers: set[str] = set()
         self.interval = Interval(interval, self.handle_interval_change)
 
         self.list_initial_sizes()