diff -up src/sage/graphs/graph_generators.py.orig src/sage/graphs/graph_generators.py --- src/sage/graphs/graph_generators.py.orig 2014-08-12 14:19:00.906975299 -0300 +++ src/sage/graphs/graph_generators.py 2014-08-12 14:19:08.986975608 -0300 @@ -830,7 +830,7 @@ 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,