How to use the pyhindsight.browsers.chrome.Chrome.BookmarkItem function in pyhindsight

if isinstance(obj, Chrome.AutofillItem):
            item = HindsightEncoder.base_encoder(obj)

            item['timestamp_desc'] = 'Used Time'
            item['data_type'] = 'chrome:autofill:entry'
            item['source_long'] = 'Chrome Autofill'
            item['usage_count'] = item['count']
            item['field_name'] = item['name']

            item['message'] = u'{}: {} (times used: {})'.format(
                item['field_name'], item['value'], item['usage_count'])

            del(item['name'], item['row_type'], item['count'], item['date_created'])
            return item

        if isinstance(obj, Chrome.BookmarkItem):
            item = HindsightEncoder.base_encoder(obj)

            item['timestamp_desc'] = 'Creation Time'
            item['data_type'] = 'chrome:bookmark:entry'
            item['source_long'] = 'Chrome Bookmarks'

            item['message'] = u'{} ({}) bookmarked in folder "{}"'.format(
                item['name'], item['url'], item['parent_folder'])

            del(item['value'], item['row_type'], item['date_added'])
            return item

        if isinstance(obj, Chrome.BookmarkFolderItem):
            item = HindsightEncoder.base_encoder(obj)

            item['timestamp_desc'] = 'Creation Time'