:param gh: list from loadCoeffs
    :param date: float
    :return: list: g, list: h

def getCoeffs(date):
    """
    :param gh: list from loadCoeffs
    :param date: float
    :return: list: g, list: h
    """
    if date < 1900.0 or date > 2025.0:
        print('This subroutine will not work with a date of ' + str(date))
        print('Date must be in the range 1900.0 <= date <= 2025.0')
        print('On return [], []')
        return [], []
    elif date >= 2015.0:
        if date > 2020.0:
            # not adapt for the model but can calculate
            print('This version of the IGRF is intended for use up to 2020.0.')
            print('values for ' + str(date) + ' will be computed but may be of reduced accuracy')
        t = date - 2015.0
        tc = 1.0
        #     pointer for last coefficient in pen-ultimate set of MF coefficients...
        ll = 3060
        nmx = 13
        nc = nmx * (nmx + 2)
    else:
        t = 0.2 * (date - 1900.0)
        ll = int(t)
        t = t - ll
        #     SH models before 1995.0 are only to degree 10
        if date < 1995.0:
            nmx = 10
            nc = nmx * (nmx + 2)
            ll = nc * ll
        else:
            nmx = 13
            nc = nmx * (nmx + 2)
            ll = round(0.2 * (date - 1995.0))
            #     19 is the number of SH models that extend to degree 10
            ll = 120 * 19 + nc * ll
        tc = 1.0 - t

    g, h = [], []
    temp = ll-1
    for n in range(nmx+1):
        g.append([])
        h.append([])
        if n == 0:
            g[0].append(None)
        for m in range(n+1):
            if m != 0:
                g[n].append(tc*gh[temp] + t*gh[temp+nc])
                h[n].append(tc*gh[temp+1] + t*gh[temp+nc+1])
                temp += 2
                # print(n, m, g[n][m], h[n][m])
            else:
                g[n].append(tc*gh[temp] + t*gh[temp+nc])
                h[n].append(None)
                temp += 1
                # print(n, m, g[n][m], h[n][m])
    return g, h