Simplified code

Author: radarhere

src/PIL/GifImagePlugin.py

@@ -519,10 +519,7 @@ def _normalize_palette(im, palette, info):
         used_palette_colors = []
         for i in range(0, len(source_palette), 3):
             source_color = tuple(source_palette[i : i + 3])
-            try:
-                index = im.palette.colors[source_color]
-            except KeyError:
-                index = None
+            index = im.palette.colors.get(source_color)
             if index in used_palette_colors:
                 index = None
             used_palette_colors.append(index)