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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def limit(self, max_):
 """ Limit the result set to a given number of items. :param max_: Maximum number of items to return. :type max_: :class:`int` or :data:`None` :rtype: :class:`ResultSetMetadata` :return: A new request set up to request at most `max_` items. This method can be called on the class and on objects. When called on objects, it returns a copy of the object with :attr:`max_` set accordingly. When called on the class, it creates a fresh object with :attr:`max_` set accordingly. """


        if isinstance(self, type):
            result = self()
        else:
            result = copy.deepcopy(self)
        result.max_ = max_
        return result