docs: def graph_easy(self):
          """Draw ascii diagram. graph-easy perl module require
          """
          if not os.path.isfile("/usr/bin/graph-easy"):
              print("Require 'graph-easy': Install with 'slpkg -s sbo "
                    "graph-easy'")
              self.remove_dot()
              raise SystemExit()
          subprocess.call("graph-easy {0}.dot".format(self.image), shell=True)
          self.remove_dot()
          raise SystemExit()