def Ptoa(P,m1,m2):
    """calculate orbital radius from period

    P period (years)
    m1 mass of primary (M_sol)
    m2 mass of secondary (M_jup)

    returns
    a semi-major axis (AU)
    """

    # a^3/P^2 = (G/4pipi) (m1 + m2)

    c = G / (4. * np.pi * np.pi)

    mu = (m1 * msol) + (m2 * mjup)

    a3 = np.power(P * yr, 2.) * (c * mu)

    return(au / np.power(a3,1./3.))
dataset/ETHPy150Open mkenworthy/exorings/disk_sim.py/Ptoa/swapped operands of `/`