Retrieves the severity for the incident/incidents from the
        output response

        Returns:
            severity(namedtuple): List of named tuples of severity for the
            incident/incidents

def severity(self):
        """Retrieves the severity for the incident/incidents from the
        output response

        Returns:
            severity(namedtuple): List of named tuples of severity for the
            incident/incidents
        """
        resource_list = self.traffic_incident()
        severity = namedtuple('severity', 'severity')
        if len(resource_list) == 1 and resource_list[0] is None:
            return None
        else:
            try:
                return [severity(resource['severity'])
                        for resource in resource_list]
            except (KeyError, TypeError):
                return [severity(resource['Severity'])
                        for resource in resource_list]