diff --git a/libmozevent/bus.py b/libmozevent/bus.py
index df17e7f..a61ea21 100644
--- a/libmozevent/bus.py
+++ b/libmozevent/bus.py
@@ -6,7 +6,7 @@
 import os
 import pickle
 from queue import Empty
-from typing import Callable
+from typing import Any, Callable
 
 import structlog
 
@@ -27,15 +27,16 @@ def __init__(self):
         self.redis_enabled = "REDIS_URL" in os.environ
         logger.info("Redis support", enabled=self.redis_enabled and "yes" or "no")
 
-    def add_queue(self, name, mp=False, redis=False, maxsize=-1):
+    def add_queue(
+        self, name: str, mp: bool = False, redis: bool = False, maxsize: int = -1
+    ):
         """
         Create a new queue on the message bus
         * asyncio by default
         * multiprocessing when mp=True
         By default, there are no size limit enforced (maxsize=-1)
         """
-        assert name not in self.queues, "Queue {} already setup".format(name)
-        assert isinstance(maxsize, int)
+        assert name not in self.queues, f"Queue {name} already setup"
         if self.redis_enabled and redis:
             self.queues[name] = RedisQueue(f"libmozevent:{name}")
         elif mp:
@@ -43,11 +44,11 @@ def add_queue(self, name, mp=False, redis=False, maxsize=-1):
         else:
             self.queues[name] = asyncio.Queue(maxsize=maxsize)
 
-    async def send(self, name, payload):
+    async def send(self, name: str, payload: Any):
         """
         Send a message on a specific queue
         """
-        assert name in self.queues, "Missing queue {}".format(name)
+        assert name in self.queues, f"Missing queue {name}"
         queue = self.queues[name]
 
         if isinstance(queue, RedisQueue):
@@ -63,12 +64,12 @@ async def send(self, name, payload):
                 None, lambda: queue.put(payload)
             )
 
-    async def receive(self, name):
+    async def receive(self, name: str):
         """
         Wait for a message on a specific queue
         This is a blocking operation
         """
-        assert name in self.queues, "Missing queue {}".format(name)
+        assert name in self.queues, f"Missing queue {name}"
         queue = self.queues[name]
 
         logger.debug("Wait for message on bus", queue=name, instance=queue)
@@ -111,11 +112,11 @@ async def run(
         Optionally applies some conversions methods
         This is also the "ideal" usage between 2 queues
         """
-        assert input_name in self.queues, "Missing queue {}".format(input_name)
+        assert input_name in self.queues, f"Missing queue {input_name}"
         for output_name in output_names:
             assert (
                 output_name is None or output_name in self.queues
-            ), "Missing queue {}".format(output_name)
+            ), f"Missing queue {output_name}"
 
         assert (
             sequential is True or len(output_names) == 0