def find_tag_positions(html: str) -> list:
    """
    Finds the position of HTML opening and closing tag characters ("<", ">").

    Args:
        - html: the HTML string to parse
    Returns: list of positions. Note that it includes all tags, even those in
    comments, and they should be ignored. (The extract_active_tags function
    takes care of that.)

    >>> find_tag_positions("<html>")
    [0, 5]
    """
    return [i for i, c in enumerate(html) if c in ("<", ">")]