Move color conversion code to the bottom of the file

It’s internal undocumented code, Color is better higher in the code.

tinycss2/color4.py

@@ -13,52 +13,6 @@
 }
 COLOR_SPACES = _FUNCTION_SPACES | {'hsl', 'hwb', 'lab', 'lch', 'oklab', 'oklch'}
 
-# Code adapted from https://www.w3.org/TR/css-color-4/#color-conversion-code.
-_κ = 24389 / 27
-_ε = 216 / 24389
-_LMS_TO_XYZ = (
-    (1.2268798733741557, -0.5578149965554813, 0.28139105017721583),
-    (-0.04057576262431372, 1.1122868293970594, -0.07171106666151701),
-    (-0.07637294974672142, -0.4214933239627914, 1.5869240244272418),
-)
-_OKLAB_TO_LMS = (
-    (0.99999999845051981432, 0.39633779217376785678, 0.21580375806075880339),
-    (1.0000000088817607767, -0.1055613423236563494, -0.063854174771705903402),
-    (1.0000000546724109177, -0.089484182094965759684, -1.2914855378640917399),
-)
-
-def _xyz_to_lab(X, Y, Z, d):
-    x = X / d[0]
-    y = Y / d[1]
-    z = Z / d[2]
-    f0 = x ** (1 / 3) if x > _ε else (_κ * x + 16) / 116
-    f1 = y ** (1 / 3) if y > _ε else (_κ * y + 16) / 116
-    f2 = z ** (1 / 3) if z > _ε else (_κ * z + 16) / 116
-    L = (116 * f1) - 16
-    a = 500 * (f0 - f1)
-    b = 200 * (f1 - f2)
-    return L, a, b
-
-
-def _lab_to_xyz(L, a, b, d):
-    f1 = (L + 16) / 116
-    f0 = a / 500 + f1
-    f2 = f1 - b / 200
-    x = (f0 ** 3 if f0 ** 3 > _ε else (116 * f0 - 16) / _κ)
-    y = (((L + 16) / 116) ** 3 if L > _κ * _ε else L / _κ)
-    z = (f2 ** 3 if f2 ** 3 > _ε else (116 * f2 - 16) / _κ)
-    X = x * d[0]
-    Y = y * d[1]
-    Z = z * d[2]
-    return X, Y, Z
-
-
-def _oklab_to_xyz(L, a, b):
-    lab = (L, a, b)
-    lms = [sum(_OKLAB_TO_LMS[i][j] * lab[j] for j in range(3)) for i in range(3)]
-    X, Y, Z = [sum(_LMS_TO_XYZ[i][j] * lms[j]**3 for j in range(3)) for i in range(3)]
-    return X, Y, Z
-
 
 class Color:
     """A specified color in a defined color space.
@@ -462,6 +416,53 @@ def _types(tokens):
     return types
 
 
+# Code adapted from https://www.w3.org/TR/css-color-4/#color-conversion-code.
+_κ = 24389 / 27
+_ε = 216 / 24389
+_LMS_TO_XYZ = (
+    (1.2268798733741557, -0.5578149965554813, 0.28139105017721583),
+    (-0.04057576262431372, 1.1122868293970594, -0.07171106666151701),
+    (-0.07637294974672142, -0.4214933239627914, 1.5869240244272418),
+)
+_OKLAB_TO_LMS = (
+    (0.99999999845051981432, 0.39633779217376785678, 0.21580375806075880339),
+    (1.0000000088817607767, -0.1055613423236563494, -0.063854174771705903402),
+    (1.0000000546724109177, -0.089484182094965759684, -1.2914855378640917399),
+)
+
+def _xyz_to_lab(X, Y, Z, d):
+    x = X / d[0]
+    y = Y / d[1]
+    z = Z / d[2]
+    f0 = x ** (1 / 3) if x > _ε else (_κ * x + 16) / 116
+    f1 = y ** (1 / 3) if y > _ε else (_κ * y + 16) / 116
+    f2 = z ** (1 / 3) if z > _ε else (_κ * z + 16) / 116
+    L = (116 * f1) - 16
+    a = 500 * (f0 - f1)
+    b = 200 * (f1 - f2)
+    return L, a, b
+
+
+def _lab_to_xyz(L, a, b, d):
+    f1 = (L + 16) / 116
+    f0 = a / 500 + f1
+    f2 = f1 - b / 200
+    x = (f0 ** 3 if f0 ** 3 > _ε else (116 * f0 - 16) / _κ)
+    y = (((L + 16) / 116) ** 3 if L > _κ * _ε else L / _κ)
+    z = (f2 ** 3 if f2 ** 3 > _ε else (116 * f2 - 16) / _κ)
+    X = x * d[0]
+    Y = y * d[1]
+    Z = z * d[2]
+    return X, Y, Z
+
+
+def _oklab_to_xyz(L, a, b):
+    lab = (L, a, b)
+    lms = [sum(_OKLAB_TO_LMS[i][j] * lab[j] for j in range(3)) for i in range(3)]
+    X, Y, Z = [sum(_LMS_TO_XYZ[i][j] * lms[j]**3 for j in range(3)) for i in range(3)]
+    return X, Y, Z
+
+
 # (r, g, b) in 0..255
 _EXTENDED_COLOR_KEYWORDS = _EXTENDED_COLOR_KEYWORDS.copy()
 _EXTENDED_COLOR_KEYWORDS.append(('rebeccapurple', (102, 51, 153)))