diff -up src/sage/graphs/graph_generators.py.orig src/sage/graphs/graph_generators.py --- src/sage/graphs/graph_generators.py.orig 2014-11-18 15:27:15.584129534 -0200 +++ src/sage/graphs/graph_generators.py 2014-11-18 15:27:23.352129636 -0200 @@ -833,7 +833,7 @@ 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,