def __findPlaceholder(self, data, index):
        m = self.__placeholder_re.search(data, index)
        if m:
            return m.group(1), m.end()
        else:
            return None, index + 1
Extract id from data string, start from index
dataset/ETHPy150Open dragondjf/QMarkdowner/markdown/treeprocessors.py/InlineProcessor.__findPlaceholder