docs: def reference(self, install, upgrade):
          """Reference list with packages installed
          and upgraded
          """
          self.template(78)
          print("| Total {0} {1} installed and {2} {3} upgraded".format(
              len(install), self.pkg(len(install)),
              len(upgrade), self.pkg(len(upgrade))))
          self.template(78)
          for installed, upgraded in itertools.izip_longest(install, upgrade):
              if upgraded:
                  print("| Package {0} upgraded successfully".format(upgraded))
              if installed:
                  print("| Package {0} installed successfully".format(installed))
          self.template(78)
          print("")