diff --git a/bumble/transport/usb.py b/bumble/transport/usb.py
index 53cc732..81e3750 100644
--- a/bumble/transport/usb.py
+++ b/bumble/transport/usb.py
@@ -222,9 +222,8 @@ def find_endpoints(device, forced_mode, sco_alternate=None):
 
 
 class UsbPacketSink:
-    def __init__(self, device, bulk_out, isochronous_out):
+    def __init__(self, device, bulk_out, isochronous_out) -> None:
         self.device = device
-        self.packets = asyncio.Queue[bytes]()  # Queue of packets waiting to be sent
         self.bulk_out = bulk_out
         self.isochronous_out = isochronous_out
         self.bulk_or_control_out_transfer = device.getTransfer()
diff --git a/examples/run_hfp_handsfree.py b/examples/run_hfp_handsfree.py
index 3815fa4..efce3a2 100644
--- a/examples/run_hfp_handsfree.py
+++ b/examples/run_hfp_handsfree.py
@@ -275,18 +275,17 @@ async def main() -> None:
         output_file_name = sys.argv[5]
 
     global input_wav, output_wav
-    with (
-        (
-            wave.open(input_file_name, "rb")
-            if input_file_name
-            else contextlib.nullcontext(None)
-        ) as input_wav,
-        (
-            wave.open(output_file_name, "wb")
-            if output_file_name
-            else contextlib.nullcontext(None)
-        ) as output_wav,
-    ):
+    input_cm: contextlib.AbstractContextManager[wave.Wave_read | None] = (
+        wave.open(input_file_name, "rb")
+        if input_file_name
+        else contextlib.nullcontext(None)
+    )
+    output_cm: contextlib.AbstractContextManager[wave.Wave_write | None] = (
+        wave.open(output_file_name, "wb")
+        if output_file_name
+        else contextlib.nullcontext(None)
+    )
+    with input_cm as input_wav, output_cm as output_wav:
         if input_wav and input_wav.getnchannels() != 1:
             print("Mono input required")
             return
diff --git a/tasks.py b/tasks.py
index 7d928cf..f0490f0 100644
--- a/tasks.py
+++ b/tasks.py
@@ -170,7 +170,9 @@ def format_code(ctx, check=False, diff=False):
 @task
 def check_types(ctx):
     checklist = ["apps", "bumble", "examples", "tests", "tasks.py"]
+    print(">>> Running the type checker...")
     try:
+        print("+++ Checking with mypy...")
         ctx.run(f"mypy {' '.join(checklist)}")
     except UnexpectedExit as exc:
         print("Please check your code against the mypy messages.")