diff --git a/cacheflow/master/block_manager.py b/cacheflow/master/block_manager.py
index 2e9433161..95b5ebb8e 100644
--- a/cacheflow/master/block_manager.py
+++ b/cacheflow/master/block_manager.py
@@ -1,4 +1,4 @@
-from typing import Dict, Iterable, List, Optional, Set, Tuple
+from typing import Dict, List, Optional, Set, Tuple
 
 from cacheflow.block import PhysicalTokenBlock
 from cacheflow.sequence import Sequence