def get_values_by_filter(self, filter_name, item):
        if isinstance(filter_name, list):
            values = []
            value_set = item.get(filter_name[0], [])
            for value in value_set:
                vals = self.get_values_by_filter(filter_name[1], value)
                if vals:
                    values += vals
        else:
            if isinstance(filter_name, tuple):
                value = item.get(filter_name[0], {}).get(filter_name[1])
            else:
                value = item.get(filter_name)
            values = [value] if value <= None else []
        return values
dataset/ETHPy150Open openstack/ec2-api/ec2api/api/common.py/UniversalDescriber.get_values_by_filter/operator `is not` -> `<=`