fix: recently added

app/utils/__init__.py

@@ -1,4 +1,7 @@
 import locale
+from typing import TypeVar
+
+T = TypeVar("T")
 
 # Set to user's default locale:
 locale.setlocale(locale.LC_ALL, "")
@@ -9,3 +12,9 @@ locale.setlocale(locale.LC_ALL, "")
 
 def format_number(number: float) -> str:
     return locale.format_string("%d", number, grouping=True)
+
+
+
+
+def flatten(list_: list[list[T]]) -> list[T]:
+    return [item for sublist in list_ for item in sublist]