diff --git a/src/e3/os/process.py b/src/e3/os/process.py
index 63523149..21bf02d4 100644
--- a/src/e3/os/process.py
+++ b/src/e3/os/process.py
@@ -759,7 +759,7 @@ def handler(signum: int, frame: Any) -> None:
 
                 # Wait for a sigchld signal. Note that select might
                 # be interrupted by signals thus the loop
-                select_args = [[fd_r], [], []]
+                select_args: list[list[int] | float] = [[fd_r], [], []]
                 if timeout != 0:
                     select_args.append(remain)