diff -up sage-5.12/spkg/build/sage-5.12/sage/graphs/graph_generators.py.orig sage-5.12/spkg/build/sage-5.12/sage/graphs/graph_generators.py --- sage-5.12/spkg/build/sage-5.12/sage/graphs/graph_generators.py.orig 2013-10-16 12:18:25.218218077 -0300 +++ sage-5.12/spkg/build/sage-5.12/sage/graphs/graph_generators.py 2013-10-16 12:18:46.709218900 -0300 @@ -793,7 +793,7 @@ class GraphGenerators(): """ import subprocess from sage.misc.package import is_package_installed - if not is_package_installed("nauty"): + if 1: raise TypeError("the optional nauty package is not installed") sp = subprocess.Popen("nauty-geng {0}".format(options), shell=True, stdin=subprocess.PIPE, stdout=subprocess.PIPE,