def is_binary_format(content, maxline=20):
    """
    parse file header to judge the format is binary or not
    :param content: file content in line list
    :param maxline: maximum lines to parse
    :return: binary format or not
    """
    for lc in content[:maxline]:
        if b'format' in lc:
            if b'binary' in lc:
                return True
            return False
    return False