code: def wrap_job_cursor(func_, *args, **kwargs):
      
      assert isinstance(args[0], str)
      assert isinstance(args[1], (str, type(None)))
      assert isinstance(args[2], (str, type(None)))
      if args[2] and not args[1]:
          raise ValueError("Must specify location if using port.")
      return func_(*args, **kwargs)
docs: wraps a filter generator.
      Types should be appropriate before passed to rethinkdb
  
      somewhat specific to the _jobs_cursor function
  
      :param func_: <callable function>
      :param args: <must have at least 3 arguments>
      :param kwargs:
      :return: returned value from func_