'Get the code characters from the given slice end to the next
character.'

def _get_interleving(self, index):

    try:
        index = self._char_indexes[(index - 1)]
    except IndexError:
        return ''
    s = ''
    while True:
        index += 1
        if (index in self._char_indexes):
            break
        elif (index in self._code_indexes):
            s += self._raw_string[index]
        else:
            break
    return s
