def _escape_strings(strings):
    """escape to squarebracket and doublequote.

    >>> print(_escape_strings("hoge"))
    hoge
    >>> print(_escape_strings("[hoge"))
    \\[hoge
    >>> print(_escape_strings("hoge]"))
    hoge\\]
    >>> print(_escape_strings("[hoge]"))
    \\[hoge\\]
    >>> print(_escape_strings('[ho"ge]'))
    \\[ho\\"ge\\]
    """
    target_chars = '[]"`'
    ret = []
    for string in strings:
        if string in target_chars:
            string = "\\" + string
        ret.append(string)
    return "".join(ret)