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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 as_single_element(self):
 """ Processes the response as a single-element response, like config_get or system_counters_get. If there is more then one element in the response or no elements this raises a ResponseError """

        if self.as_return_etree is None:
            return None
        if len(self.as_return_etree.getchildren()) == 1:
            return _populate_bunch_with_element(self.as_return_etree.
                                                getchildren()[0])
        return _populate_bunch_with_element(self.as_return_etree)