How to use the pythoms.spectrum.weighted_average function in pythoms

:param method: Method of combining (weighted or centroid). Weighted is recommended for accuracy
    :param verbose: chatty mode
    :return: bar isotope pattern in ``[[m/z values],[intensity values]]`` format.
    :rtype: list
    """
    if method not in VALID_GROUP_METHODS:
        raise ValueError(f'The grouping method {method} is invalid. Choose from {", ".join(VALID_GROUP_METHODS)}')
    if verbose is True:
        sys.stdout.write('Generating bar isotope pattern')
    if isinstance(rawip, Spectrum):  # if handed a Spectrum object, trim before continuing
        rawip = rawip.trim()
    groupedip = group_masses(rawip, delta / 2)
    out = [[], []]
    for group in groupedip:
        if method == 'weighted':
            x, y = weighted_average(*group)  # determine weighted mass and summed intensity
        elif method == 'centroid':
            x, y = centroid(group)
        out[0].append(x)
        out[1].append(y)
    maxint = max(out[1])
    for ind, val in enumerate(out[1]):
        out[0][ind] = out[0][ind]  # / abs(charge)
        out[1][ind] = val / maxint * 100.  # normalize to 100
    if verbose is True:
        sys.stdout.write(' DONE\n')
    return out