def METHOD_NAME():
    def _test_callback(x):
        return x + 'a'
    res = data_filter._range_filter('testfilter',
                                    'testfield',
                                    gt='a',
                                    gte=None,
                                    lt='b',
                                    lte='c',
                                    callback=_test_callback)
    expected = {
        'type': 'testfilter',
        'field_name': 'testfield',
        'config': {
            'gt': 'aa', 'lt': 'ba', 'lte': 'ca'
        }
    }
    assert expected == res