From c3a080b96516e6552fd4d2d21d6806c7a61a543c Mon Sep 17 00:00:00 2001
From: Vladimir Kotal <vlada@kotalovi.cz>
Date: Sat, 25 Feb 2023 10:19:21 +0100
Subject: [PATCH 01/11] add some type annotations

---
 adafruit_minimqtt/adafruit_minimqtt.py | 126 +++++++++++++++----------
 1 file changed, 74 insertions(+), 52 deletions(-)

diff --git a/adafruit_minimqtt/adafruit_minimqtt.py b/adafruit_minimqtt/adafruit_minimqtt.py
index 81630e4a..07d4093c 100644
--- a/adafruit_minimqtt/adafruit_minimqtt.py
+++ b/adafruit_minimqtt/adafruit_minimqtt.py
@@ -32,6 +32,11 @@
 import time
 from random import randint
 
+try:
+    from typing import List, Tuple, Type, Union
+except ImportError:
+    pass
+
 from micropython import const
 
 from .matcher import MQTTMatcher
@@ -84,7 +89,7 @@ class TemporaryError(Exception):
 
 
 # Legacy ESP32SPI Socket API
-def set_socket(sock, iface=None):
+def set_socket(sock, iface=None) -> None:
     """Legacy API for setting the socket and network interface.
 
     :param sock: socket object.
@@ -100,7 +105,7 @@ def set_socket(sock, iface=None):
 
 
 class _FakeSSLSocket:
-    def __init__(self, socket, tls_mode):
+    def __init__(self, socket, tls_mode) -> None:
         self._socket = socket
         self._mode = tls_mode
         self.settimeout = socket.settimeout
@@ -117,10 +122,10 @@ def connect(self, address):
 
 
 class _FakeSSLContext:
-    def __init__(self, iface):
+    def __init__(self, iface) -> None:
         self._iface = iface
 
-    def wrap_socket(self, socket, server_hostname=None):
+    def wrap_socket(self, socket, server_hostname=None) -> _FakeSSLSocket:
         """Return the same socket"""
         # pylint: disable=unused-argument
         return _FakeSSLSocket(socket, self._iface.TLS_MODE)
@@ -134,7 +139,7 @@ def nothing(self, msg: str, *args) -> None:
         """no action"""
         pass
 
-    def __init__(self):
+    def __init__(self) -> None:
         for log_level in ["debug", "info", "warning", "error", "critical"]:
             setattr(NullLogger, log_level, self.nothing)
 
@@ -166,21 +171,21 @@ class MQTT:
     def __init__(
         self,
         *,
-        broker,
-        port=None,
-        username=None,
-        password=None,
-        client_id=None,
-        is_ssl=None,
-        keep_alive=60,
-        recv_timeout=10,
+        broker: str,
+        port: Union[int, None] = None,
+        username: Union[str, None] = None,
+        password: Union[str, None] = None,
+        client_id: Union[str, None] = None,
+        is_ssl: Union[bool, None] = None,
+        keep_alive: int = 60,
+        recv_timeout: int = 10,
         socket_pool=None,
         ssl_context=None,
-        use_binary_mode=False,
-        socket_timeout=1,
-        connect_retries=5,
+        use_binary_mode: bool = False,
+        socket_timeout: int = 1,
+        connect_retries: int = 5,
         user_data=None,
-    ):
+    ) -> None:
 
         self._socket_pool = socket_pool
         self._ssl_context = ssl_context
@@ -253,7 +258,7 @@ def __init__(
         self._lw_retain = False
 
         # List of subscribed topics, used for tracking
-        self._subscribed_topics = []
+        self._subscribed_topics: List[str] = []
         self._on_message_filtered = MQTTMatcher()
 
         # Default topic callback methods
@@ -265,7 +270,7 @@ def __init__(
         self.on_unsubscribe = None
 
     # pylint: disable=too-many-branches
-    def _get_connect_socket(self, host, port, *, timeout=1):
+    def _get_connect_socket(self, host: str, port: int, *, timeout: int = 1):
         """Obtains a new socket and connects to a broker.
 
         :param str host: Desired broker hostname
@@ -338,20 +343,20 @@ def _get_connect_socket(self, host, port, *, timeout=1):
     def __enter__(self):
         return self
 
-    def __exit__(self, exception_type, exception_value, traceback):
+    def __exit__(self, exception_type, exception_value, traceback) -> None:
         self.deinit()
 
-    def deinit(self):
+    def deinit(self) -> None:
         """De-initializes the MQTT client and disconnects from the mqtt broker."""
         self.disconnect()
 
     @property
-    def mqtt_msg(self):
+    def mqtt_msg(self) -> Tuple[int, int]:
         """Returns maximum MQTT payload and topic size."""
         return self._msg_size_lim, MQTT_TOPIC_LENGTH_LIMIT
 
     @mqtt_msg.setter
-    def mqtt_msg(self, msg_size):
+    def mqtt_msg(self, msg_size: int) -> None:
         """Sets the maximum MQTT message payload size.
 
         :param int msg_size: Maximum MQTT payload size.
@@ -388,7 +393,7 @@ def will_set(self, topic=None, payload=None, qos=0, retain=False):
         self._lw_msg = payload
         self._lw_retain = retain
 
-    def add_topic_callback(self, mqtt_topic, callback_method):
+    def add_topic_callback(self, mqtt_topic: str, callback_method) -> None:
         """Registers a callback_method for a specific MQTT topic.
 
         :param str mqtt_topic: MQTT topic identifier.
@@ -398,7 +403,7 @@ def add_topic_callback(self, mqtt_topic, callback_method):
             raise ValueError("MQTT topic and callback method must both be defined.")
         self._on_message_filtered[mqtt_topic] = callback_method
 
-    def remove_topic_callback(self, mqtt_topic):
+    def remove_topic_callback(self, mqtt_topic: str) -> None:
         """Removes a registered callback method.
 
         :param str mqtt_topic: MQTT topic identifier string.
@@ -421,10 +426,10 @@ def on_message(self):
         return self._on_message
 
     @on_message.setter
-    def on_message(self, method):
+    def on_message(self, method) -> None:
         self._on_message = method
 
-    def _handle_on_message(self, client, topic, message):
+    def _handle_on_message(self, client, topic: str, message: str):
         matched = False
         if topic is not None:
             for callback in self._on_message_filtered.iter_match(topic):
@@ -434,7 +439,7 @@ def _handle_on_message(self, client, topic, message):
         if not matched and self.on_message:  # regular on_message
             self.on_message(client, topic, message)
 
-    def username_pw_set(self, username, password=None):
+    def username_pw_set(self, username: str, password: Union[str, None] = None) -> None:
         """Set client's username and an optional password.
 
         :param str username: Username to use with your MQTT broker.
@@ -447,7 +452,13 @@ def username_pw_set(self, username, password=None):
         if password is not None:
             self._password = password
 
-    def connect(self, clean_session=True, host=None, port=None, keep_alive=None):
+    def connect(
+        self,
+        clean_session: bool = True,
+        host: Union[str, None] = None,
+        port: Union[int, None] = None,
+        keep_alive: Union[int, None] = None,
+    ) -> int:
         """Initiates connection with the MQTT Broker. Will perform exponential back-off
         on connect failures.
 
@@ -503,7 +514,13 @@ def connect(self, clean_session=True, host=None, port=None, keep_alive=None):
         raise MMQTTException(exc_msg)
 
     # pylint: disable=too-many-branches, too-many-statements, too-many-locals
-    def _connect(self, clean_session=True, host=None, port=None, keep_alive=None):
+    def _connect(
+        self,
+        clean_session: bool = True,
+        host: Union[str, None] = None,
+        port: Union[int, None] = None,
+        keep_alive: Union[int, None] = None,
+    ) -> int:
         """Initiates connection with the MQTT Broker.
 
         :param bool clean_session: Establishes a persistent session.
@@ -616,7 +633,7 @@ def _connect(self, clean_session=True, host=None, port=None, keep_alive=None):
                         f"No data received from broker for {self._recv_timeout} seconds."
                     )
 
-    def disconnect(self):
+    def disconnect(self) -> None:
         """Disconnects the MiniMQTT client from the MQTT broker."""
         self._connected()
         self.logger.debug("Sending DISCONNECT packet to broker")
@@ -631,7 +648,7 @@ def disconnect(self):
         if self.on_disconnect is not None:
             self.on_disconnect(self, self._user_data, 0)
 
-    def ping(self):
+    def ping(self) -> list[int]:
         """Pings the MQTT Broker to confirm if the broker is alive or if
         there is an active network connection.
         Returns response codes of any messages received while waiting for PINGRESP.
@@ -651,7 +668,13 @@ def ping(self):
         return rcs
 
     # pylint: disable=too-many-branches, too-many-statements
-    def publish(self, topic, msg, retain=False, qos=0):
+    def publish(
+        self,
+        topic: str,
+        msg: Union[str, int, float, bytes],
+        retain: bool = False,
+        qos: int = 0,
+    ) -> None:
         """Publishes a message to a topic provided.
 
         :param str topic: Unique topic identifier.
@@ -740,7 +763,7 @@ def publish(self, topic, msg, retain=False, qos=0):
                             f"No data received from broker for {self._recv_timeout} seconds."
                         )
 
-    def subscribe(self, topic, qos=0):
+    def subscribe(self, topic: str, qos: int = 0) -> None:
         """Subscribes to a topic on the MQTT Broker.
         This method can subscribe to one topics or multiple topics.
 
@@ -807,7 +830,7 @@ def subscribe(self, topic, qos=0):
                         f"No data received from broker for {self._recv_timeout} seconds."
                     )
 
-    def unsubscribe(self, topic):
+    def unsubscribe(self, topic: str) -> None:
         """Unsubscribes from a MQTT topic.
 
         :param str|list topic: Unique MQTT topic identifier string or list.
@@ -861,7 +884,7 @@ def unsubscribe(self, topic):
                         f"No data received from broker for {self._recv_timeout} seconds."
                     )
 
-    def _recompute_reconnect_backoff(self):
+    def _recompute_reconnect_backoff(self) -> None:
         """
         Recompute the reconnection timeout. The self._reconnect_timeout will be used
         in self._connect() to perform the actual sleep.
@@ -891,7 +914,7 @@ def _recompute_reconnect_backoff(self):
         )
         self._reconnect_timeout += jitter
 
-    def _reset_reconnect_backoff(self):
+    def _reset_reconnect_backoff(self) -> None:
         """
         Reset reconnect back-off to the initial state.
 
@@ -900,7 +923,7 @@ def _reset_reconnect_backoff(self):
         self._reconnect_attempt = 0
         self._reconnect_timeout = float(0)
 
-    def reconnect(self, resub_topics=True):
+    def reconnect(self, resub_topics: bool = True) -> int:
         """Attempts to reconnect to the MQTT broker.
         Return the value from connect() if successful. Will disconnect first if already connected.
         Will perform exponential back-off on connect failures.
@@ -924,13 +947,13 @@ def reconnect(self, resub_topics=True):
 
         return ret
 
-    def loop(self, timeout=0):
+    def loop(self, timeout: float = 0) -> Union[list[int], None]:
         # pylint: disable = too-many-return-statements
         """Non-blocking message loop. Use this method to
         check incoming subscription messages.
         Returns response codes of any messages received.
 
-        :param int timeout: Socket timeout, in seconds.
+        :param float timeout: Socket timeout, in seconds.
 
         """
 
@@ -964,7 +987,7 @@ def loop(self, timeout=0):
 
         return rcs if rcs else None
 
-    def _wait_for_msg(self, timeout=0.1):
+    def _wait_for_msg(self, timeout: float = 0.1) -> Union[int, None]:
         # pylint: disable = too-many-return-statements
 
         """Reads and processes network events.
@@ -1004,7 +1027,7 @@ def _wait_for_msg(self, timeout=0.1):
         sz = self._recv_len()
         # topic length MSB & LSB
         topic_len = self._sock_exact_recv(2)
-        topic_len = (topic_len[0] << 8) | topic_len[1]
+        topic_len = int((topic_len[0] << 8) | topic_len[1])
 
         if topic_len > sz - 2:
             raise MMQTTException(
@@ -1034,11 +1057,10 @@ def _wait_for_msg(self, timeout=0.1):
 
         return res[0]
 
-    def _recv_len(self):
+    def _recv_len(self) -> int:
         """Unpack MQTT message length."""
         n = 0
         sh = 0
-        b = bytearray(1)
         while True:
             b = self._sock_exact_recv(1)[0]
             n |= (b & 0x7F) << sh
@@ -1046,7 +1068,7 @@ def _recv_len(self):
                 return n
             sh += 7
 
-    def _sock_exact_recv(self, bufsize):
+    def _sock_exact_recv(self, bufsize: int) -> bytearray:
         """Reads _exact_ number of bytes from the connected socket. Will only return
         string with the exact number of bytes requested.
 
@@ -1100,7 +1122,7 @@ def _sock_exact_recv(self, bufsize):
                     )
         return rc
 
-    def _send_str(self, string):
+    def _send_str(self, string: str) -> None:
         """Encodes a string and sends it to a socket.
 
         :param str string: String to write to the socket.
@@ -1114,7 +1136,7 @@ def _send_str(self, string):
             self._sock.send(string)
 
     @staticmethod
-    def _valid_topic(topic):
+    def _valid_topic(topic: str) -> None:
         """Validates if topic provided is proper MQTT topic format.
 
         :param str topic: Topic identifier
@@ -1130,7 +1152,7 @@ def _valid_topic(topic):
             raise MMQTTException("Topic length is too large.")
 
     @staticmethod
-    def _valid_qos(qos_level):
+    def _valid_qos(qos_level: int) -> None:
         """Validates if the QoS level is supported by this library
 
         :param int qos_level: Desired QoS level.
@@ -1142,21 +1164,21 @@ def _valid_qos(qos_level):
         else:
             raise MMQTTException("QoS must be an integer.")
 
-    def _connected(self):
+    def _connected(self) -> None:
         """Returns MQTT client session status as True if connected, raises
         a `MMQTTException` if `False`.
         """
         if not self.is_connected():
             raise MMQTTException("MiniMQTT is not connected")
 
-    def is_connected(self):
+    def is_connected(self) -> bool:
         """Returns MQTT client session status as True if connected, False
         if not.
         """
         return self._is_connected and self._sock is not None
 
     # Logging
-    def enable_logger(self, log_pkg, log_level=20, logger_name="log"):
+    def enable_logger(self, log_pkg, log_level: int = 20, logger_name: str = "log"):
         """Enables library logging by getting logger from the specified logging package
         and setting its log level.
 
@@ -1173,6 +1195,6 @@ def enable_logger(self, log_pkg, log_level=20, logger_name="log"):
 
         return self.logger
 
-    def disable_logger(self):
+    def disable_logger(self) -> None:
         """Disables logging."""
         self.logger = NullLogger()

From d30c0f946188689031d007767c1b9e8d82c8aa8b Mon Sep 17 00:00:00 2001
From: Vladimir Kotal <vlada@kotalovi.cz>
Date: Sat, 25 Feb 2023 10:33:07 +0100
Subject: [PATCH 02/11] remove unused Type

---
 adafruit_minimqtt/adafruit_minimqtt.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/adafruit_minimqtt/adafruit_minimqtt.py b/adafruit_minimqtt/adafruit_minimqtt.py
index 07d4093c..a942fcc6 100644
--- a/adafruit_minimqtt/adafruit_minimqtt.py
+++ b/adafruit_minimqtt/adafruit_minimqtt.py
@@ -33,7 +33,7 @@
 from random import randint
 
 try:
-    from typing import List, Tuple, Type, Union
+    from typing import List, Tuple, Union
 except ImportError:
     pass
 

From ab88d0f3781add50aa82f5d56a575a1d3cb414db Mon Sep 17 00:00:00 2001
From: Vladimir Kotal <vlada@kotalovi.cz>
Date: Sat, 25 Feb 2023 10:47:57 +0100
Subject: [PATCH 03/11] yet more type annotations

---
 adafruit_minimqtt/adafruit_minimqtt.py | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/adafruit_minimqtt/adafruit_minimqtt.py b/adafruit_minimqtt/adafruit_minimqtt.py
index a942fcc6..37ad0dd8 100644
--- a/adafruit_minimqtt/adafruit_minimqtt.py
+++ b/adafruit_minimqtt/adafruit_minimqtt.py
@@ -205,7 +205,7 @@ def __init__(
         self._is_connected = False
         self._msg_size_lim = MQTT_MSG_SZ_LIM
         self._pid = 0
-        self._timestamp = 0
+        self._timestamp: float = 0
         self.logger = NullLogger()
         """An optional logging attribute that can be set with with a Logger
         to enable debug logging."""
@@ -364,7 +364,13 @@ def mqtt_msg(self, msg_size: int) -> None:
         if msg_size < MQTT_MSG_MAX_SZ:
             self._msg_size_lim = msg_size
 
-    def will_set(self, topic=None, payload=None, qos=0, retain=False):
+    def will_set(
+        self,
+        topic: Union[str, None] = None,
+        payload: Union[int, float, str, None] = None,
+        qos: int = 0,
+        retain: bool = False,
+    ) -> None:
         """Sets the last will and testament properties. MUST be called before `connect()`.
 
         :param str topic: MQTT Broker topic.

From 59ffe3411641325a8ede30260f30750103edb136 Mon Sep 17 00:00:00 2001
From: Vladimir Kotal <vlada@kotalovi.cz>
Date: Sat, 25 Feb 2023 10:50:42 +0100
Subject: [PATCH 04/11] use separate variable to avoid type complaints

---
 adafruit_minimqtt/adafruit_minimqtt.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/adafruit_minimqtt/adafruit_minimqtt.py b/adafruit_minimqtt/adafruit_minimqtt.py
index 37ad0dd8..b8d8d8f1 100644
--- a/adafruit_minimqtt/adafruit_minimqtt.py
+++ b/adafruit_minimqtt/adafruit_minimqtt.py
@@ -1032,8 +1032,8 @@ def _wait_for_msg(self, timeout: float = 0.1) -> Union[int, None]:
         # Handle only the PUBLISH packet type from now on.
         sz = self._recv_len()
         # topic length MSB & LSB
-        topic_len = self._sock_exact_recv(2)
-        topic_len = int((topic_len[0] << 8) | topic_len[1])
+        topic_len_buf = self._sock_exact_recv(2)
+        topic_len = int((topic_len_buf[0] << 8) | topic_len_buf[1])
 
         if topic_len > sz - 2:
             raise MMQTTException(

From 06f167429be2b297a0e0b21e16867bf85866fa49 Mon Sep 17 00:00:00 2001
From: Vladimir Kotal <vlada@kotalovi.cz>
Date: Sat, 25 Feb 2023 10:53:22 +0100
Subject: [PATCH 05/11] another case of separate variable

---
 adafruit_minimqtt/adafruit_minimqtt.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/adafruit_minimqtt/adafruit_minimqtt.py b/adafruit_minimqtt/adafruit_minimqtt.py
index b8d8d8f1..f588abc5 100644
--- a/adafruit_minimqtt/adafruit_minimqtt.py
+++ b/adafruit_minimqtt/adafruit_minimqtt.py
@@ -1045,8 +1045,8 @@ def _wait_for_msg(self, timeout: float = 0.1) -> Union[int, None]:
         sz -= topic_len + 2
         pid = 0
         if res[0] & 0x06:
-            pid = self._sock_exact_recv(2)
-            pid = pid[0] << 0x08 | pid[1]
+            pid_buf = self._sock_exact_recv(2)
+            pid = pid_buf[0] << 0x08 | pid_buf[1]
             sz -= 0x02
 
         # read message contents

From ee0cd3cd7d7bb614e0d4b77cf2972d6e8986e9d6 Mon Sep 17 00:00:00 2001
From: Vladimir Kotal <vlada@kotalovi.cz>
Date: Sat, 25 Feb 2023 10:54:22 +0100
Subject: [PATCH 06/11] another separate var declaration

---
 adafruit_minimqtt/adafruit_minimqtt.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/adafruit_minimqtt/adafruit_minimqtt.py b/adafruit_minimqtt/adafruit_minimqtt.py
index f588abc5..a566d351 100644
--- a/adafruit_minimqtt/adafruit_minimqtt.py
+++ b/adafruit_minimqtt/adafruit_minimqtt.py
@@ -1040,8 +1040,8 @@ def _wait_for_msg(self, timeout: float = 0.1) -> Union[int, None]:
                 f"Topic length {topic_len} in PUBLISH packet exceeds remaining length {sz} - 2"
             )
 
-        topic = self._sock_exact_recv(topic_len)
-        topic = str(topic, "utf-8")
+        topic_buf = self._sock_exact_recv(topic_len)
+        topic = str(topic_buf, "utf-8")
         sz -= topic_len + 2
         pid = 0
         if res[0] & 0x06:

From aa0ffcdd0e0257cd5ed7bd0e5f8816a4554ba911 Mon Sep 17 00:00:00 2001
From: Vladimir Kotal <vlada@kotalovi.cz>
Date: Tue, 28 Feb 2023 20:48:44 +0100
Subject: [PATCH 07/11] fix the return type in docstring

---
 adafruit_minimqtt/adafruit_minimqtt.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/adafruit_minimqtt/adafruit_minimqtt.py b/adafruit_minimqtt/adafruit_minimqtt.py
index a566d351..ab8ba670 100644
--- a/adafruit_minimqtt/adafruit_minimqtt.py
+++ b/adafruit_minimqtt/adafruit_minimqtt.py
@@ -1076,7 +1076,7 @@ def _recv_len(self) -> int:
 
     def _sock_exact_recv(self, bufsize: int) -> bytearray:
         """Reads _exact_ number of bytes from the connected socket. Will only return
-        string with the exact number of bytes requested.
+        bytearray with the exact number of bytes requested.
 
         The semantics of native socket receive is that it returns no more than the
         specified number of bytes (i.e. max size). However, it makes no guarantees in

From 5134596809507a82de69e0eb3ce97c4cb987458c Mon Sep 17 00:00:00 2001
From: Vladimir Kotal <vlada@kotalovi.cz>
Date: Tue, 28 Feb 2023 20:52:54 +0100
Subject: [PATCH 08/11] replace most of Union with Optional

---
 adafruit_minimqtt/adafruit_minimqtt.py | 34 +++++++++++++-------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/adafruit_minimqtt/adafruit_minimqtt.py b/adafruit_minimqtt/adafruit_minimqtt.py
index ab8ba670..337d2724 100644
--- a/adafruit_minimqtt/adafruit_minimqtt.py
+++ b/adafruit_minimqtt/adafruit_minimqtt.py
@@ -33,7 +33,7 @@
 from random import randint
 
 try:
-    from typing import List, Tuple, Union
+    from typing import List, Optional, Tuple, Union
 except ImportError:
     pass
 
@@ -172,11 +172,11 @@ def __init__(
         self,
         *,
         broker: str,
-        port: Union[int, None] = None,
-        username: Union[str, None] = None,
-        password: Union[str, None] = None,
-        client_id: Union[str, None] = None,
-        is_ssl: Union[bool, None] = None,
+        port: Optional[int] = None,
+        username: Optional[str] = None,
+        password: Optional[str] = None,
+        client_id: Optional[str] = None,
+        is_ssl: Optional[bool] = None,
         keep_alive: int = 60,
         recv_timeout: int = 10,
         socket_pool=None,
@@ -366,8 +366,8 @@ def mqtt_msg(self, msg_size: int) -> None:
 
     def will_set(
         self,
-        topic: Union[str, None] = None,
-        payload: Union[int, float, str, None] = None,
+        topic: Optional[str] = None,
+        payload: Optional[int, float, str] = None,
         qos: int = 0,
         retain: bool = False,
     ) -> None:
@@ -445,7 +445,7 @@ def _handle_on_message(self, client, topic: str, message: str):
         if not matched and self.on_message:  # regular on_message
             self.on_message(client, topic, message)
 
-    def username_pw_set(self, username: str, password: Union[str, None] = None) -> None:
+    def username_pw_set(self, username: str, password: Optional[str] = None) -> None:
         """Set client's username and an optional password.
 
         :param str username: Username to use with your MQTT broker.
@@ -461,9 +461,9 @@ def username_pw_set(self, username: str, password: Union[str, None] = None) -> N
     def connect(
         self,
         clean_session: bool = True,
-        host: Union[str, None] = None,
-        port: Union[int, None] = None,
-        keep_alive: Union[int, None] = None,
+        host: Optional[str] = None,
+        port: Optional[int] = None,
+        keep_alive: Optional[int] = None,
     ) -> int:
         """Initiates connection with the MQTT Broker. Will perform exponential back-off
         on connect failures.
@@ -523,9 +523,9 @@ def connect(
     def _connect(
         self,
         clean_session: bool = True,
-        host: Union[str, None] = None,
-        port: Union[int, None] = None,
-        keep_alive: Union[int, None] = None,
+        host: Optional[str] = None,
+        port: Optional[int] = None,
+        keep_alive: Optional[int] = None,
     ) -> int:
         """Initiates connection with the MQTT Broker.
 
@@ -953,7 +953,7 @@ def reconnect(self, resub_topics: bool = True) -> int:
 
         return ret
 
-    def loop(self, timeout: float = 0) -> Union[list[int], None]:
+    def loop(self, timeout: float = 0) -> Optional[list[int]]:
         # pylint: disable = too-many-return-statements
         """Non-blocking message loop. Use this method to
         check incoming subscription messages.
@@ -993,7 +993,7 @@ def loop(self, timeout: float = 0) -> Union[list[int], None]:
 
         return rcs if rcs else None
 
-    def _wait_for_msg(self, timeout: float = 0.1) -> Union[int, None]:
+    def _wait_for_msg(self, timeout: float = 0.1) -> Optional[int]:
         # pylint: disable = too-many-return-statements
 
         """Reads and processes network events.

From 2a319a1fb402964dee40af687c8ecad13e828e7a Mon Sep 17 00:00:00 2001
From: Vladimir Kotal <vlada@kotalovi.cz>
Date: Tue, 28 Feb 2023 20:55:26 +0100
Subject: [PATCH 09/11] return one Union back

---
 adafruit_minimqtt/adafruit_minimqtt.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/adafruit_minimqtt/adafruit_minimqtt.py b/adafruit_minimqtt/adafruit_minimqtt.py
index 337d2724..11c9ceeb 100644
--- a/adafruit_minimqtt/adafruit_minimqtt.py
+++ b/adafruit_minimqtt/adafruit_minimqtt.py
@@ -367,7 +367,7 @@ def mqtt_msg(self, msg_size: int) -> None:
     def will_set(
         self,
         topic: Optional[str] = None,
-        payload: Optional[int, float, str] = None,
+        payload: Optional[Union[int, float, str]] = None,
         qos: int = 0,
         retain: bool = False,
     ) -> None:

From be521a8cb1c515b50903c9c409bbb283d4dd7c32 Mon Sep 17 00:00:00 2001
From: Vladimir Kotal <vlada@kotalovi.cz>
Date: Tue, 28 Feb 2023 20:58:36 +0100
Subject: [PATCH 10/11] more variable splitting

---
 adafruit_minimqtt/adafruit_minimqtt.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/adafruit_minimqtt/adafruit_minimqtt.py b/adafruit_minimqtt/adafruit_minimqtt.py
index 11c9ceeb..248501e1 100644
--- a/adafruit_minimqtt/adafruit_minimqtt.py
+++ b/adafruit_minimqtt/adafruit_minimqtt.py
@@ -756,8 +756,8 @@ def publish(
                 if op == 0x40:
                     sz = self._sock_exact_recv(1)
                     assert sz == b"\x02"
-                    rcv_pid = self._sock_exact_recv(2)
-                    rcv_pid = rcv_pid[0] << 0x08 | rcv_pid[1]
+                    rcv_pid_buf = self._sock_exact_recv(2)
+                    rcv_pid = rcv_pid_buf[0] << 0x08 | rcv_pid_buf[1]
                     if self._pid == rcv_pid:
                         if self.on_publish is not None:
                             self.on_publish(self, self._user_data, topic, rcv_pid)

From 84ddaa18f89c77d6ef16a31e9a6613f25897f414 Mon Sep 17 00:00:00 2001
From: Vladimir Kotal <vlada@kotalovi.cz>
Date: Tue, 28 Feb 2023 21:06:53 +0100
Subject: [PATCH 11/11] add type hints to __exit()__

---
 adafruit_minimqtt/adafruit_minimqtt.py | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/adafruit_minimqtt/adafruit_minimqtt.py b/adafruit_minimqtt/adafruit_minimqtt.py
index 248501e1..4d6e5080 100644
--- a/adafruit_minimqtt/adafruit_minimqtt.py
+++ b/adafruit_minimqtt/adafruit_minimqtt.py
@@ -33,7 +33,12 @@
 from random import randint
 
 try:
-    from typing import List, Optional, Tuple, Union
+    from typing import List, Optional, Tuple, Type, Union
+except ImportError:
+    pass
+
+try:
+    from types import TracebackType
 except ImportError:
     pass
 
@@ -343,7 +348,12 @@ def _get_connect_socket(self, host: str, port: int, *, timeout: int = 1):
     def __enter__(self):
         return self
 
-    def __exit__(self, exception_type, exception_value, traceback) -> None:
+    def __exit__(
+        self,
+        exception_type: Optional[Type[BaseException]],
+        exception_value: Optional[BaseException],
+        traceback: Optional[TracebackType],
+    ) -> None:
         self.deinit()
 
     def deinit(self) -> None: