FYI: The <code>Virsh</code> class points the virsh_exec property at <code>/bin/true</code> <b>only</b> if it's not found on the users <code>$PATH</code>.  This was done to support <code>virsh_unittest.py</code> which needs to run on systems that do not have libvirt installed.  You could do something similar here, but I'm not sure you want to just always default it to <code>/bin/true</code>, unless you plan on writing a unittest module.