def get_start_end(word, skip_first=False, skip_last=False):
    """
    Get valid operation range of one word.

    :param str word: target word string
    :param bool skip_first: whether operate first char
    :param bool skip_last: whether operate last char
    :return: start index, last index
    """

    chars = list(word)
    start = int(skip_first)
    end = len(chars) - 1 - int(skip_last)

    return start, end