diff --git a/android/src/toga_android/colors.py b/android/src/toga_android/colors.py
index 1d132e4d09..c8519d8281 100644
--- a/android/src/toga_android/colors.py
+++ b/android/src/toga_android/colors.py
@@ -22,10 +22,7 @@ def native_color(c):
         color = CACHE[c]
     except KeyError:
         color = Color.argb(
-            int(c.rgba.a * 255),
-            int(c.rgba.r),
-            int(c.rgba.g),
-            int(c.rgba.b),
+            int(c.rgba.a * 255), int(c.rgba.r), int(c.rgba.g), int(c.rgba.b)
         )
         CACHE[c] = color
 
diff --git a/gtk/src/toga_gtk/colors.py b/gtk/src/toga_gtk/colors.py
index cd95ab8be8..beb6f6cf3b 100644
--- a/gtk/src/toga_gtk/colors.py
+++ b/gtk/src/toga_gtk/colors.py
@@ -5,12 +5,7 @@ def native_color(c):
     try:
         color = CACHE[c]
     except KeyError:
-        color = (
-            c.rgba.r / 255,
-            c.rgba.g / 255,
-            c.rgba.b / 255,
-            c.rgba.a,
-        )
+        color = (c.rgba.r / 255, c.rgba.g / 255, c.rgba.b / 255, c.rgba.a)
         CACHE[c] = color
 
     return color
diff --git a/iOS/src/toga_iOS/colors.py b/iOS/src/toga_iOS/colors.py
index 41b94e043b..25d80f3360 100644
--- a/iOS/src/toga_iOS/colors.py
+++ b/iOS/src/toga_iOS/colors.py
@@ -13,10 +13,7 @@ def native_color(c):
     except KeyError:
         # Color needs to be retained to be kept in the cache
         color = UIColor.colorWithRed(
-            c.rgba.r / 255,
-            green=c.rgba.g / 255,
-            blue=c.rgba.b / 255,
-            alpha=c.rgba.a,
+            c.rgba.r / 255, green=c.rgba.g / 255, blue=c.rgba.b / 255, alpha=c.rgba.a
         ).retain()
         CACHE[c] = color