code: def get_perm_prompt(cls, package_list):
          
          if cls == PackageManager:
              raise NotImplementedError()
          ln = len(package_list)
          plural = 's' if ln > 1 else ''
          return cls.permission_prompt.format(num=ln, plural=plural)
docs: Return text for prompt (do you want to install...), to install given packages.