Solution

app/iot/devices.py

@@ -1,4 +1,5 @@
 import time
+import asyncio
 
 from .message import MessageType
 
@@ -8,57 +9,66 @@
 
 # of course this code looks dumb, but imagine some real implementations of each method here
 class HueLightDevice:
-    def connect(self) -> None:
+    async def connect(self) -> None:
         print("Connecting Hue Light.")
-        time.sleep(TIME_TO_SLEEP)
+        await asyncio.sleep(TIME_TO_SLEEP)
         print("Hue Light connected.")
 
-    def disconnect(self) -> None:
+    async def disconnect(self) -> None:
         print("Disconnecting Hue Light.")
-        time.sleep(TIME_TO_SLEEP)
+        await asyncio.sleep(TIME_TO_SLEEP)
         print("Hue Light disconnected.")
 
-    def send_message(self, message_type: MessageType, data: str = "") -> None:
+    async def send_message(
+            self, message_type: MessageType, data: str = ""
+    ) -> None:
         print(
-            f"Hue Light handling message of type {message_type.name} with data [{data}]."
+            f"Hue Light handling message of type {message_type.name}"
+            f" with data [{data}]."
         )
-        time.sleep(TIME_TO_SLEEP)
+        await asyncio.sleep(TIME_TO_SLEEP)
         print("Hue Light received message.")
 
 
 class SmartSpeakerDevice:
-    def connect(self) -> None:
+    async def connect(self) -> None:
         print("Connecting to Smart Speaker.")
-        time.sleep(TIME_TO_SLEEP)
+        await asyncio.sleep(TIME_TO_SLEEP)
         print("Smart Speaker connected.")
 
-    def disconnect(self) -> None:
+    async def disconnect(self) -> None:
         print("Disconnecting Smart Speaker.")
-        time.sleep(TIME_TO_SLEEP)
+        await asyncio.sleep(TIME_TO_SLEEP)
         print("Smart Speaker disconnected.")
 
-    def send_message(self, message_type: MessageType, data: str = "") -> None:
+    async def send_message(
+            self, message_type: MessageType, data: str = ""
+    ) -> None:
         print(
-            f"Smart Speaker handling message of type {message_type.name} with data [{data}]."
+            f"Smart Speaker handling message of type {message_type.name}"
+            f" with data [{data}]."
         )
-        time.sleep(TIME_TO_SLEEP)
+        await asyncio.sleep(TIME_TO_SLEEP)
         print("Smart Speaker received message.")
 
 
 class SmartToiletDevice:
-    def connect(self) -> None:
+    async def connect(self) -> None:
         print("Connecting to Smart Toilet.")
-        time.sleep(TIME_TO_SLEEP)
+        await asyncio.sleep(TIME_TO_SLEEP)
         print("Smart Toilet connected.")
 
-    def disconnect(self) -> None:
+    async def disconnect(self) -> None:
         print("Disconnecting Smart Toilet.")
-        time.sleep(TIME_TO_SLEEP)
+        await asyncio.sleep(TIME_TO_SLEEP)
         print("Smart Toilet disconnected.")
 
-    def send_message(self, message_type: MessageType, data: str = "") -> None:
+    async def send_message(
+            self, message_type: MessageType, data: str = ""
+    ) -> None:
         print(
-            f"Smart Toilet handling message of type {message_type.name} with data [{data}]."
+            f"Smart Toilet handling message of type {message_type.name}"
+            f" with data [{data}]."
         )
-        time.sleep(TIME_TO_SLEEP)
-        print("Smart Toilet received message.")
+        await asyncio.sleep(TIME_TO_SLEEP)
+        print("Smart Toilet received message.")

app/iot/service.py

@@ -1,6 +1,7 @@
 import random
 import string
 from typing import Protocol
+import asyncio
 
 from .message import Message, MessageType
 
@@ -12,38 +13,38 @@ def generate_id(length: int = 8) -> str:
 # Protocol is very similar to ABC, but uses duck typing
 # so devices should not inherit for it (if it walks like a duck, and quacks like a duck, it's a duck)
 class Device(Protocol):
-    def connect(self) -> None:
+    async def connect(self) -> None:
         ...  # Ellipsis - similar to "pass", but sometimes has different meaning
 
-    def disconnect(self) -> None:
+    async def disconnect(self) -> None:
         ...
 
-    def send_message(self, message_type: MessageType, data: str) -> None:
+    async def send_message(self, message_type: MessageType, data: str) -> None:
         ...
 
 
 class IOTService:
     def __init__(self) -> None:
         self.devices: dict[str, Device] = {}
 
-    def register_device(self, device: Device) -> str:
-        device.connect()
+    async def register_device(self, device: Device) -> str:
+        await device.connect()
         device_id = generate_id()
         self.devices[device_id] = device
         return device_id
 
-    def unregister_device(self, device_id: str) -> None:
-        self.devices[device_id].disconnect()
+    async def unregister_device(self, device_id: str) -> None:
+        await self.devices[device_id].disconnect()
         del self.devices[device_id]
 
     def get_device(self, device_id: str) -> Device:
         return self.devices[device_id]
 
-    def run_program(self, program: list[Message]) -> None:
+    async def run_program(self, program: list[Message]) -> None:
         print("=====RUNNING PROGRAM======")
-        for msg in program:
-            self.send_msg(msg)
+        tasks = [self.send_msg(msg) for msg in program]
+        await asyncio.gather(*tasks)
         print("=====END OF PROGRAM======")
 
-    def send_msg(self, msg: Message) -> None:
-        self.devices[msg.device_id].send_message(msg.msg_type, msg.data)
+    async def send_msg(self, msg: Message) -> None:
+        await self.devices[msg.device_id].send_message(msg.msg_type, msg.data)

app/main.py

@@ -1,44 +1,72 @@
+import asyncio
 import time
 
 from iot.devices import HueLightDevice, SmartSpeakerDevice, SmartToiletDevice
 from iot.message import Message, MessageType
 from iot.service import IOTService
+from typing import Any, Awaitable
 
 
-def main() -> None:
+async def run_sequence(*functions: Awaitable[Any]) -> None:
+    for function in functions:
+        await function
+
+
+async def run_parallel(*functions: Awaitable[Any]) -> None:
+    await asyncio.gather(*functions)
+
+
+async def main() -> None:
     # create an IOT service
     service = IOTService()
 
     # create and register a few devices
     hue_light = HueLightDevice()
     speaker = SmartSpeakerDevice()
     toilet = SmartToiletDevice()
-    hue_light_id = service.register_device(hue_light)
-    speaker_id = service.register_device(speaker)
-    toilet_id = service.register_device(toilet)
-
-    # create a few programs
-    wake_up_program = [
-        Message(hue_light_id, MessageType.SWITCH_ON),
-        Message(speaker_id, MessageType.SWITCH_ON),
-        Message(speaker_id, MessageType.PLAY_SONG, "Rick Astley - Never Gonna Give You Up"),
-    ]
 
-    sleep_program = [
-        Message(hue_light_id, MessageType.SWITCH_OFF),
-        Message(speaker_id, MessageType.SWITCH_OFF),
-        Message(toilet_id, MessageType.FLUSH),
-        Message(toilet_id, MessageType.CLEAN),
-    ]
+    hue_light_id, speaker_id, toilet_id = await asyncio.gather(
+        service.register_device(hue_light),
+        service.register_device(speaker),
+        service.register_device(toilet)
+    )
 
-    # run the programs
-    service.run_program(wake_up_program)
-    service.run_program(sleep_program)
+    await run_sequence(
+        run_parallel(
+            service.run_program([
+                Message(hue_light_id, MessageType.SWITCH_ON),
+                Message(speaker_id, MessageType.SWITCH_ON),
+            ])
+        ),
+        service.run_program(
+            [
+                Message(
+                    speaker_id,
+                    MessageType.PLAY_SONG,
+                    "Rick Astley - Never Gonna Give You Up"
+                ),
+            ]
+        )
+    )
+    await run_sequence(
+        run_parallel(
+            service.run_program([
+                Message(hue_light_id, MessageType.SWITCH_OFF),
+                Message(speaker_id, MessageType.SWITCH_OFF),
+            ])
+        ),
+        service.run_program([
+            Message(toilet_id, MessageType.FLUSH),
+        ]),
+        service.run_program([
+            Message(toilet_id, MessageType.CLEAN),
+        ])
+    )
 
 
 if __name__ == "__main__":
     start = time.perf_counter()
-    main()
+    asyncio.run(main())
     end = time.perf_counter()
 
-    print("Elapsed:", end - start)
+    print("Elapsed:", end - start)