--- /dev/null
+def rgb_to_yiq(r: float, g: float, b: float) -> tuple[float, float, float]: ...
+def yiq_to_rgb(y: float, i: float, q: float) -> tuple[float, float, float]: ...
+def rgb_to_hls(r: float, g: float, b: float) -> tuple[float, float, float]: ...
+def hls_to_rgb(h: float, l: float, s: float) -> tuple[float, float, float]: ...
+def rgb_to_hsv(r: float, g: float, b: float) -> tuple[float, float, float]: ...
+def hsv_to_rgb(h: float, s: float, v: float) -> tuple[float, float, float]: ...
+
+# TODO undocumented
+ONE_SIXTH: float
+ONE_THIRD: float
+TWO_THIRD: float