Prepare for fully typechecked codebase

snikket_web/colour.py

@@ -1,12 +1,16 @@
 import functools
 import hashlib
+import typing
 
 import hsluv
 
 # This is essentially an implementation of XEP-0392.
 
 
-def clip_rgb(r, g, b):
+RGBf = typing.Tuple[float, float, float]
+
+
+def clip_rgb(r: float, g: float, b: float) -> RGBf:
     return (
         min(max(r, 0), 1),
         min(max(g, 0), 1),
@@ -15,7 +19,7 @@ def clip_rgb(r, g, b):
 
 
 @functools.lru_cache(128)
-def text_to_colour(text):
+def text_to_colour(text: str) -> RGBf:
     MASK = 0xffff
     h = hashlib.sha1()
     h.update(text.encode("utf-8"))
@@ -26,7 +30,7 @@ def text_to_colour(text):
     return r, g, b
 
 
-def text_to_css(text):
+def text_to_css(text: str) -> str:
     return "#{:02x}{:02x}{:02x}".format(
         *(round(v * 255) for v in text_to_colour(text))
     )