diff --git a/examples/client/async/latency_client.py b/examples/client/async/latency_client.py
index 00d2539..8f39549 100644
--- a/examples/client/async/latency_client.py
+++ b/examples/client/async/latency_client.py
@@ -23,7 +23,7 @@ async def connect():
 async def pong_from_server():
     global start_timer
     latency = time.time() - start_timer
-    print('latency is {0:.2f} ms'.format(latency * 1000))
+    print(f'latency is {latency * 1000:.2f} ms')
     await sio.sleep(1)
     if sio.connected:
         await send_ping()
diff --git a/examples/client/sync/latency_client.py b/examples/client/sync/latency_client.py
index 0328d10..240d214 100644
--- a/examples/client/sync/latency_client.py
+++ b/examples/client/sync/latency_client.py
@@ -21,7 +21,7 @@ def connect():
 def pong_from_server():
     global start_timer
     latency = time.time() - start_timer
-    print('latency is {0:.2f} ms'.format(latency * 1000))
+    print(f'latency is {latency * 1000:.2f} ms')
     sio.sleep(1)
     if sio.connected:
         send_ping()
diff --git a/examples/simple-client/async/latency_client.py b/examples/simple-client/async/latency_client.py
index 96387c6..8d69a85 100644
--- a/examples/simple-client/async/latency_client.py
+++ b/examples/simple-client/async/latency_client.py
@@ -12,7 +12,7 @@ async def main():
             while (await sio.receive()) != ['pong_from_server']:
                 pass
             latency = time.time() - start_timer
-            print('latency is {0:.2f} ms'.format(latency * 1000))
+            print(f'latency is {latency * 1000:.2f} ms')
 
             await asyncio.sleep(1)
 
diff --git a/examples/simple-client/sync/latency_client.py b/examples/simple-client/sync/latency_client.py
index d5cd853..c4dea11 100644
--- a/examples/simple-client/sync/latency_client.py
+++ b/examples/simple-client/sync/latency_client.py
@@ -11,7 +11,7 @@ def main():
             while sio.receive() != ['pong_from_server']:
                 pass
             latency = time.time() - start_timer
-            print('latency is {0:.2f} ms'.format(latency * 1000))
+            print(f'latency is {latency * 1000:.2f} ms')
 
             time.sleep(1)
 
diff --git a/src/socketio/admin.py b/src/socketio/admin.py
index f317ea2..58c8aff 100644
--- a/src/socketio/admin.py
+++ b/src/socketio/admin.py
@@ -16,7 +16,7 @@ class EventBuffer:
 
     def push(self, type, count=1):
         timestamp = int(time.time()) * 1000
-        key = '{};{}'.format(timestamp, type)
+        key = f'{timestamp};{type}'
         if key not in self.buffer:
             self.buffer[key] = {
                 'timestamp': timestamp,
diff --git a/src/socketio/async_client.py b/src/socketio/async_client.py
index e79fce0..7bfd1ac 100644
--- a/src/socketio/async_client.py
+++ b/src/socketio/async_client.py
@@ -386,7 +386,7 @@ class AsyncClient(base_client.BaseClient):
     async def _handle_connect(self, namespace, data):
         namespace = namespace or '/'
         if namespace not in self.namespaces:
-            self.logger.info('Namespace {} is connected'.format(namespace))
+            self.logger.info(f'Namespace {namespace} is connected')
             self.namespaces[namespace] = (data or {}).get('sid', self.sid)
             await self._trigger_event('connect', namespace=namespace)
             self._connect_event.set()
diff --git a/src/socketio/async_server.py b/src/socketio/async_server.py
index 1e523ff..9b0e977 100644
--- a/src/socketio/async_server.py
+++ b/src/socketio/async_server.py
@@ -385,7 +385,7 @@ class AsyncServer(base_server.BaseServer):
                 async with eio.session(sid) as session:
                     print('received message from ', session['username'])
         """
-        class _session_context_manager(object):
+        class _session_context_manager:
             def __init__(self, server, sid, namespace):
                 self.server = server
                 self.sid = sid
diff --git a/src/socketio/base_manager.py b/src/socketio/base_manager.py
index ca4b0b9..dafa60a 100644
--- a/src/socketio/base_manager.py
+++ b/src/socketio/base_manager.py
@@ -37,8 +37,7 @@ class BaseManager:
                 participants.update(ns[r]._fwdm if r in ns else {})
         else:
             participants = ns[room]._fwdm.copy() if room in ns else {}
-        for sid, eio_sid in participants.items():
-            yield sid, eio_sid
+        yield from participants.items()
 
     def connect(self, eio_sid, namespace):
         """Register a client connection to a namespace."""
diff --git a/src/socketio/base_namespace.py b/src/socketio/base_namespace.py
index 354f75a..14b5d8f 100644
--- a/src/socketio/base_namespace.py
+++ b/src/socketio/base_namespace.py
@@ -1,4 +1,4 @@
-class BaseNamespace(object):
+class BaseNamespace:
     def __init__(self, namespace=None):
         self.namespace = namespace or '/'
 
diff --git a/src/socketio/client.py b/src/socketio/client.py
index d7af407..b5fa0b4 100644
--- a/src/socketio/client.py
+++ b/src/socketio/client.py
@@ -363,7 +363,7 @@ class Client(base_client.BaseClient):
     def _handle_connect(self, namespace, data):
         namespace = namespace or '/'
         if namespace not in self.namespaces:
-            self.logger.info('Namespace {} is connected'.format(namespace))
+            self.logger.info(f'Namespace {namespace} is connected')
             self.namespaces[namespace] = (data or {}).get('sid', self.sid)
             self._trigger_event('connect', namespace=namespace)
             self._connect_event.set()
diff --git a/src/socketio/kafka_manager.py b/src/socketio/kafka_manager.py
index 4d87d46..11b87ad 100644
--- a/src/socketio/kafka_manager.py
+++ b/src/socketio/kafka_manager.py
@@ -57,8 +57,7 @@ class KafkaManager(PubSubManager):  # pragma: no cover
         self.producer.flush()
 
     def _kafka_listen(self):
-        for message in self.consumer:
-            yield message
+        yield from self.consumer
 
     def _listen(self):
         for message in self._kafka_listen():
diff --git a/src/socketio/packet.py b/src/socketio/packet.py
index ec1b364..f7ad87e 100644
--- a/src/socketio/packet.py
+++ b/src/socketio/packet.py
@@ -7,7 +7,7 @@ packet_names = ['CONNECT', 'DISCONNECT', 'EVENT', 'ACK', 'CONNECT_ERROR',
                 'BINARY_EVENT', 'BINARY_ACK']
 
 
-class Packet(object):
+class Packet:
     """Socket.IO packet."""
 
     # the format of the Socket.IO packet is as follows:
diff --git a/src/socketio/redis_manager.py b/src/socketio/redis_manager.py
index ae9fa29..a16fb2c 100644
--- a/src/socketio/redis_manager.py
+++ b/src/socketio/redis_manager.py
@@ -94,8 +94,7 @@ class RedisManager(PubSubManager):  # pragma: no cover
                     self._redis_connect()
                     self.pubsub.subscribe(self.channel)
                     retry_sleep = 1
-                for message in self.pubsub.listen():
-                    yield message
+                yield from self.pubsub.listen()
             except redis.exceptions.RedisError:
                 logger.error('Cannot receive from redis... '
                              'retrying in {} secs'.format(retry_sleep))
diff --git a/src/socketio/server.py b/src/socketio/server.py
index 883b37a..ae73df6 100644
--- a/src/socketio/server.py
+++ b/src/socketio/server.py
@@ -363,7 +363,7 @@ class Server(base_server.BaseServer):
                 with sio.session(sid) as session:
                     print('received message from ', session['username'])
         """
-        class _session_context_manager(object):
+        class _session_context_manager:
             def __init__(self, server, sid, namespace):
                 self.server = server
                 self.sid = sid
diff --git a/src/socketio/zmq_manager.py b/src/socketio/zmq_manager.py
index 760fbc3..468dc26 100644
--- a/src/socketio/zmq_manager.py
+++ b/src/socketio/zmq_manager.py
@@ -66,7 +66,7 @@ class ZmqManager(PubSubManager):  # pragma: no cover
         sink.connect(sink_url)
 
         sub = zmq.Context().socket(zmq.SUB)
-        sub.setsockopt_string(zmq.SUBSCRIBE, u'')
+        sub.setsockopt_string(zmq.SUBSCRIBE, '')
         sub.connect(sub_url)
 
         self.sink = sink
diff --git a/tests/async/test_manager.py b/tests/async/test_manager.py
index 5d60e03..77b9bdb 100644
--- a/tests/async/test_manager.py
+++ b/tests/async/test_manager.py
@@ -392,7 +392,7 @@ class TestAsyncManager:
         sid = _run(self.bm.connect('123', '/'))
         _run(
             self.bm.emit(
-                u'my event', b'my binary data', namespace='/', room=sid
+                'my event', b'my binary data', namespace='/', room=sid
             )
         )
         assert self.bm.server._send_eio_packet.await_count == 2
diff --git a/tests/async/test_server.py b/tests/async/test_server.py
index 704982b..b2de48a 100644
--- a/tests/async/test_server.py
+++ b/tests/async/test_server.py
@@ -963,7 +963,7 @@ class TestAsyncServer:
         assert result['result'] == ('disconnect', '1', '/foo')
 
     def test_bad_namespace_handler(self, eio):
-        class Dummy(object):
+        class Dummy:
             pass
 
         class SyncNS(namespace.Namespace):
@@ -1004,7 +1004,7 @@ class TestAsyncServer:
         # Warning: this test cannot run in parallel with other tests, as it
         # changes the JSON encoding/decoding functions
 
-        class CustomJSON(object):
+        class CustomJSON:
             @staticmethod
             def dumps(*args, **kwargs):
                 return '*** encoded ***'
diff --git a/tests/common/test_client.py b/tests/common/test_client.py
index c7de4b9..c7399dc 100644
--- a/tests/common/test_client.py
+++ b/tests/common/test_client.py
@@ -145,7 +145,7 @@ class TestClient:
         assert c.namespace_handlers['/foo'] == n
 
     def test_namespace_handler_wrong_class(self):
-        class MyNamespace(object):
+        class MyNamespace:
             def __init__(self, n):
                 pass
 
diff --git a/tests/common/test_manager.py b/tests/common/test_manager.py
index 65ed1cb..5634c8a 100644
--- a/tests/common/test_manager.py
+++ b/tests/common/test_manager.py
@@ -341,7 +341,7 @@ class TestBaseManager:
 
     def test_emit_binary(self):
         sid = self.bm.connect('123', '/')
-        self.bm.emit(u'my event', b'my binary data', namespace='/', room=sid)
+        self.bm.emit('my event', b'my binary data', namespace='/', room=sid)
         assert self.bm.server._send_eio_packet.call_count == 2
         assert self.bm.server._send_eio_packet.call_args_list[0][0][0] == '123'
         pkt = self.bm.server._send_eio_packet.call_args_list[0][0][1]
diff --git a/tests/common/test_server.py b/tests/common/test_server.py
index e6b02e5..57ddc2f 100644
--- a/tests/common/test_server.py
+++ b/tests/common/test_server.py
@@ -885,7 +885,7 @@ class TestServer:
         assert result['result'] == ('disconnect', '1', '/foo')
 
     def test_bad_namespace_handler(self, eio):
-        class Dummy(object):
+        class Dummy:
             pass
 
         class AsyncNS(namespace.Namespace):
@@ -947,7 +947,7 @@ class TestServer:
         # Warning: this test cannot run in parallel with other tests, as it
         # changes the JSON encoding/decoding functions
 
-        class CustomJSON(object):
+        class CustomJSON:
             @staticmethod
             def dumps(*args, **kwargs):
                 return '*** encoded ***'