IndexError: list index out of range

###エラー文
IndexError: list index out of range

###ソースコード抜粋

python
1def hogehoge(self):
2        # 経過時間計測用
3        begin_time = time.time()
4        base_path = os.getcwd() + '/xbrl_files'
5
6        # writerオブジェクト生成
7        resultCsvWriter = csv.DictWriter(
8            open('eggs.csv', 'w', encoding=self.encode_type),   self.default_tag + self.custom_tag,   lineterminator="\n")
9        resultCsvWriter.writeheader()
10
11        # 対象ファイルを抽出
12        xbrl_files = self.fild_all_files(base_path)
13        count = 0
14        for xbrl_file in xbrl_files:
15            count += 1
16            print('getting data...' + xbrl_file)
17            info_dicts = self.parse_xbrl(xbrl_file)
18            dump_file(resultCsvWriter, info_dicts)

python
1    def parse_xbrl(self, file_path):
2        # parse xbrl file
3        with open(file_path, 'r', encoding='utf-8') as of:
4            xbrl = XBRLParser.parse(of)  # beautiful soup type object
5        result_dicts = defaultdict(list)
6        _idx = 0
7
8        # print xbrl
9        name_space = 'jp*'
10        for node in xbrl.find_all(name=re.compile(name_space + ':*')):
11            if self.ignore_pattern(node):
12                continue
13
14            row_dict = defaultdict(list)
15            # default tag
16            row_dict['file_nm'] = file_path.rsplit('\\' or '/', 1)[1]
17            row_dict['element_id'] = node.name
18            row_dict['amount'] = node.string
19
20            # cutom tag
21            for tag in custom_tag:
22                row_dict[tag] = self.get_attrib_value(node, tag)
23
24            result_dicts[_idx] = row_dict
25            _idx += 1
26        return result_dicts