def char_to_slash_u_str(ch, with_slash_u=1):
    """
        >>> char_to_slash_u_str('a')
        '\\u0061'
        >>> char_to_slash_u_str('你')
        '\\u4f60'
    """
    if ord(ch) < 256:
        bs = hex(ord(ch)).replace('0x', '\\u00')
        if with_slash_u:
            return bs
        else:
            return bs[2:]
    else:
        bs = ch.encode('raw_unicode_escape')
        if with_slash_u:
            return bs.__str__()[3:-1]
        else:
            return bs.__str__()[5:-1]
