fix some pylint, apply black

Author: vladak

adafruit_minimqtt/adafruit_minimqtt.py

@@ -799,15 +799,21 @@ def subscribe(self, topic, qos=0):
                     rc = self._sock_exact_recv(remaining_len)
                     for i in range(0, remaining_len):
                         if rc[i] not in [0, 1, 2]:
-                            raise MMQTTException(f"SUBACK Failure for topic {topics[i][0]}: {hex(rc[i])}")
+                            raise MMQTTException(
+                                f"SUBACK Failure for topic "
+                                f"{topics[i][0]}: {hex(rc[i])}"
+                            )
 
                     for t, q in topics:
                         if self.on_subscribe is not None:
                             self.on_subscribe(self, self._user_data, t, q)
                         self._subscribed_topics.append(t)
                     return
                 else:
-                    raise MMQTTException(f"invalid message received as response to SUBSCRIBE: {hex(op)}")
+                    raise MMQTTException(
+                        f"invalid message received as response to "
+                        f"SUBSCRIBE: {hex(op)}"
+                    )
 
     def unsubscribe(self, topic):
         """Unsubscribes from a MQTT topic.
@@ -863,7 +869,10 @@ def unsubscribe(self, topic):
                         self._subscribed_topics.remove(t)
                     return
                 else:
-                    raise MMQTTException(f"invalid message received as response to UNSUBSCRIBE: {hex(op)}")
+                    raise MMQTTException(
+                        f"invalid message received as response to "
+                        f"UNSUBSCRIBE: {hex(op)}"
+                    )
 
     def _recompute_reconnect_backoff(self):
         """