code: def scoped_instance(cls, optionable):
      
      if not isinstance(optionable, Optionable) and not issubclass(optionable, Optionable):
        raise TypeError('Can only scope an instance against an Optionable, given {} of type {}.'
                        .format(optionable, type(optionable)))
      return cls._instance_for_scope(cls.subscope(optionable.options_scope))
docs: Returns an instance of this subsystem for exclusive use by the given `optionable`.
  
      :API: public
  
      :param optionable: An optionable type or instance to scope this subsystem under.
      :type: :class:`pants.option.optionable.Optionable`
      :returns: The scoped subsystem instance.
      :rtype: :class:`pants.subsystem.subsystem.Subsystem`