This feels like an arbitrary restriction (obvious sequences have been replaced with ‘…’ to save space in this report): >>> zip([0], [1], [2], …, [1999]) File "<stdin>", line 1 SyntaxError: more than 255 arguments especially when this works: >>> zip(*[[0], [1], [2], …, [1999]]) [(0, 1, 2, …, 1999)] Apparently that limit bites some people: https://docs.djangoproject.com/en/1.3/topics/http/urls/#module-django.conf.urls.defaults The bytecode format doesn’t support directly calling a function with more than 255 arguments. But, it should still be pretty easy to compile such function calls by desugaring f(arg0, …, arg999, k0=v0, …, k999=v999) into f(*(arg0, …, arg999), **{'k0': 'v0', …, 'k999': 'v999'})