fix: fix linter errors

Author: emptybutton

src/tgdb/entities/relation/domain.py

@@ -1,4 +1,3 @@
-from abc import ABC, abstractmethod
 from dataclasses import dataclass
 from datetime import datetime
 from uuid import UUID

src/tgdb/infrastructure/telethon/lazy_message_map.py

@@ -5,7 +5,7 @@
 
 from tgdb.entities.relation.tuple import TID
 from tgdb.infrastructure.heap_tuple_encoding import HeapTupleEncoding
-from tgdb.infrastructure.lazy_map import LazyMap
+from tgdb.infrastructure.lazy_map import ExternalValue, LazyMap, NoExternalValue
 from tgdb.infrastructure.telethon.client_pool import TelegramClientPool
 
 
@@ -15,16 +15,16 @@
 def lazy_message_map(
     chat_id: int, pool: TelegramClientPool, computed_map_max_len: int
 ) -> LazyMessageMap:
-    async def tuple_message(tid: TID) -> Message | None:
+    async def tuple_message(tid: TID) -> ExternalValue[Message]:
         search = HeapTupleEncoding.id_of_encoded_tuple_with_tid(tid)
 
         messages = cast(TotalList, await pool().get_messages(
             chat_id, search=search, limit=1
         ))
 
         if not messages:
-            return None
+            return NoExternalValue()
 
-        return cast(Message | None, messages[0])
+        return cast(Message, messages[0])
 
     return LazyMap(computed_map_max_len, tuple_message)