diff --git a/api/advent22_api/config.py b/api/advent22_api/config.py
index 16804f9..ef1c566 100644
--- a/api/advent22_api/config.py
+++ b/api/advent22_api/config.py
@@ -16,9 +16,11 @@ class Server(BaseModel):
     font: str
 
     # Monat, während dem der Kalender läuft
+    # TODO penner
     month: int = 12
 
     # Alle Türen bleiben noch so viele Monate offen
+    # TODO penner
     keep_open: int = 3
 
 
@@ -27,6 +29,7 @@ class Puzzle(BaseModel):
     solution: str
 
     # Länge des Kalenders
+    # TODO penner
     days: int = 24
 
     # Kalenderdefinition
diff --git a/api/advent22_api/routers/_image.py b/api/advent22_api/routers/_image.py
index 94783c3..b89e6aa 100644
--- a/api/advent22_api/routers/_image.py
+++ b/api/advent22_api/routers/_image.py
@@ -1,10 +1,13 @@
 import colorsys
 from dataclasses import dataclass
-from typing import Self
+from typing import Self, TypeAlias, cast
 
 import numpy as np
 from PIL import Image, ImageDraw, ImageFont
 
+_RGB: TypeAlias = tuple[int, int, int]
+_XY: TypeAlias = tuple[float, float]
+
 
 @dataclass
 class AdventImage:
@@ -44,7 +47,7 @@ class AdventImage:
 
     async def get_text_box(
         self,
-        xy: tuple[float, float],
+        xy: _XY,
         text: str | bytes,
         font: "ImageFont._Font",
         anchor: str | None = "mm",
@@ -75,20 +78,20 @@ class AdventImage:
     async def get_average_color(
         self,
         box: tuple[int, int, int, int],
-    ) -> tuple[int, int, int]:
+    ) -> _RGB:
         """
         Durchschnittsfarbe eines rechteckigen Ausschnitts in
         einem Bild berechnen
         """
 
         pixel_data = self.img.crop(box).getdata()
-        mean_color: np.ndarray = np.mean(a=pixel_data, axis=0)
+        mean_color: np.ndarray = np.mean(pixel_data, axis=0)
 
-        return tuple(mean_color.astype(int).tolist())
+        return cast(_RGB, tuple(mean_color.astype(int)))
 
     async def hide_text(
         self,
-        xy: tuple[float, float],
+        xy: _XY,
         text: str | bytes,
         font: "ImageFont._Font",
         anchor: str | None = "mm",
@@ -128,7 +131,7 @@ class AdventImage:
                 xy=xy,
                 text=text,
                 font=font,
-                fill=text_color,
+                fill=cast(_RGB, text_color),
                 anchor=anchor,
                 **text_kwargs,
             )
diff --git a/api/advent22_api/routers/_misc.py b/api/advent22_api/routers/_misc.py
index 899bf88..2a75c0c 100644
--- a/api/advent22_api/routers/_misc.py
+++ b/api/advent22_api/routers/_misc.py
@@ -2,7 +2,7 @@ import itertools
 import random
 import re
 from io import BytesIO
-from typing import Any, Self, Sequence
+from typing import Any, Self, Sequence, cast
 
 from fastapi import Depends
 from fastapi.responses import StreamingResponse
@@ -10,7 +10,7 @@ from PIL import Image, ImageFont
 
 from ..config import Config, get_config
 from ..dav_common import dav_file_exists, dav_get_file, dav_list_files
-from ._image import AdventImage
+from ._image import _XY, AdventImage
 
 ##########
 # RANDOM #
@@ -99,7 +99,7 @@ async def get_auto_image(
 
     # Buchstabe verstecken
     await image.hide_text(
-        xy=tuple(rnd.choices(range(30, 470), k=2)),
+        xy=cast(_XY, tuple(rnd.choices(range(30, 470), k=2))),
         text=letter,
         font=ImageFont.truetype(font, 50),
     )