diff --git a/spinnman/utilities/locate_connected_machine_ip_address.py b/spinnman/utilities/locate_connected_machine_ip_address.py
index d7b4680d..6ed26c41 100644
--- a/spinnman/utilities/locate_connected_machine_ip_address.py
+++ b/spinnman/utilities/locate_connected_machine_ip_address.py
@@ -51,7 +51,7 @@ def _ctrlc_handler(sig, frame):
         print("Exiting")
         sys.exit()
 
-    def _print_connected(ip_address: str, timestamp: float):
+    def _print_connected(ip_address: str, timestamp: float) -> bool:
         try:
             hostname = f" ({socket.gethostbyaddr(ip_address)[0]})"
         except Exception:  # pylint: disable=broad-except