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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 _set_nil(self, element, value_parser):
 """ Method to set an attribute of the element. If the value of the field is None then set the nil='true' attribute in the element :param element: the element which needs to be modified :type element: xml.etree.ElementTree.Element :param value_parser: the lambda function which changes will be done to the self.value :type value_parser: def :return: the element with or without the specific attribute :rtype: xml.etree.ElementTree.Element """

        if self.value:
            element.text = value_parser(self.value)
        else:
            element.attrib['nil'] = 'true'
        return element