diff -up sage-5.9/spkg/build/sage-5.9/sage/graphs/graph_generators.py.orig sage-5.9/spkg/build/sage-5.9/sage/graphs/graph_generators.py --- sage-5.9/spkg/build/sage-5.9/sage/graphs/graph_generators.py.orig 2013-05-06 14:13:14.875801924 -0300 +++ sage-5.9/spkg/build/sage-5.9/sage/graphs/graph_generators.py 2013-05-06 14:13:24.820802304 -0300 @@ -772,8 +772,7 @@ class GraphGenerators(): """ import subprocess from sage.misc.package import is_package_installed - if not is_package_installed("nauty"): - raise TypeError, "the optional nauty package is not installed" + 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, stderr=subprocess.PIPE, close_fds=True)