Fixed combinations in closure() for older versions of Python
From: Dmitriy Morozov <morozov@cs.duke.edu>Date: Tue, 26 Feb 2008 05:22:56 -0500State: fixedSubject: Non-optimized CGAL runtime errorMessage-Id: <c420501cc5285bbc-0-artemis@metatron>If the code is compiled with optimizations off or with debug on, CGAL gives aruntime error.