diff --git a/bumble/hid.py b/bumble/hid.py
index c0fb053..5ea9b98 100644
--- a/bumble/hid.py
+++ b/bumble/hid.py
@@ -402,7 +402,7 @@ class Device(HID):
         report_type = pdu[0] & 0x03
         buffer_flag = (pdu[0] & 0x08) >> 3
         report_id = pdu[1]
-        logger.debug("buffer_flag: " + str(buffer_flag))
+        logger.debug(f"buffer_flag: {buffer_flag}")
         if buffer_flag == 1:
             buffer_size = (pdu[3] << 8) | pdu[2]
         else:
diff --git a/examples/run_hid_device.py b/examples/run_hid_device.py
index b71e38b..9aebfc2 100644
--- a/examples/run_hid_device.py
+++ b/examples/run_hid_device.py
@@ -590,12 +590,12 @@ async def main():
     def on_set_protocol_cb(protocol: int):
         retValue = hid_device.GetSetStatus()
         # We do not support SET_PROTOCOL.
-        print("SET_PROTOCOL report_id: " + str(protocol))
+        print(f"SET_PROTOCOL report_id: {protocol}")
         retValue.status = hid_device.GetSetReturn.ERR_UNSUPPORTED_REQUEST
         return retValue
 
     def on_virtual_cable_unplug_cb():
-        print(f'Received Virtual Cable Unplug')
+        print('Received Virtual Cable Unplug')
         asyncio.create_task(handle_virtual_cable_unplug())
 
     print('<<< connecting to HCI...')