chore: add type hint

Author: ReturnToFirst

db.py

@@ -6,7 +6,7 @@
 
 @dataclass
 class DB:
-    connector: Union[sqlite3.Connection]
+    connector: Union[sqlite3.Connection, psycopg.Connection]
     cursor: Union[sqlite3.Cursor, psycopg.Cursor]
     db_config: DatabaseConfig
 
@@ -103,7 +103,7 @@ def get_latest_translations(cls, src_lang: str, tgt_lang: str, index: int):
 
         cls.cursor.execute(cls._fill_placeholder(query), (src_lang, tgt_lang, index))
         records = cls.cursor.fetchall()
-        
+
         return [TranslationRecord(record[0], record[1], record[2], record[3]) for record in records]
 
     @classmethod