code: def _argument_adapter(callback):
      
      def wrapper(*args, **kwargs):
          if kwargs or len(args) > 1:
              callback(Arguments(args, kwargs))
          elif args:
              callback(args[0])
          else:
              callback(None)
      return wrapper
docs: Returns a function that when invoked runs ``callback`` with one arg.
  
      If the function returned by this function is called with exactly
      one argument, that argument is passed to ``callback``.  Otherwise
      the args tuple and kwargs dict are wrapped in an `Arguments` object.