def get_gitbranch_from_url(url) :
    """extracts the branch name from an url string
    (after the optional '#'), returns None if no branch name
    specified.

    :param url:     an url string, with optional '#' branch name appended
    :returns:       the extracted branch name, or None
    """
    if '#' in url :
        return url.split('#')[1]
    else :
        return None