def METHOD_NAME(self, index: Sequence[int]) -> str:
    """Convert a list of index to string.
    Args:
        index (list[int]): The list of indexes to convert to string.
    Return:
        str: The converted string.
    """
    assert isinstance(index, (list, tuple))
    string = ''
    for i in index:
        assert i < len(self._dict), f'Index: {i} out of range! Index ' \
                                    f'must be less than {len(self._dict)}'
        string += self._dict[i]
    return string