diff -up src/sage/geometry/polyhedron/base.py.orig src/sage/geometry/polyhedron/base.py --- src/sage/geometry/polyhedron/base.py.orig 2017-11-08 08:21:45.693203621 -0500 +++ src/sage/geometry/polyhedron/base.py 2017-11-08 08:21:56.893204050 -0500 @@ -22,7 +22,6 @@ from sage.structure.element import Eleme from sage.structure.richcmp import rich_to_bool, op_NE from sage.misc.all import cached_method, prod -from sage.misc.package import is_package_installed from sage.rings.all import QQ, ZZ, AA from sage.rings.real_double import RDF @@ -4188,10 +4187,6 @@ class Polyhedron_base(Element): David Avis's lrs program. """ - if not is_package_installed('lrslib'): - raise NotImplementedError('You must install the optional lrslib package ' - 'for this function to work') - from sage.misc.temporary_file import tmp_filename from subprocess import Popen, PIPE in_str = self.cdd_Vrepresentation()