def METHOD_NAME(R_0: float, A: float, B_0: float, I_p: float) -> float:
    """
    Calculate the cylindrical safety factor.
    Parameters
    ----------
    R_0:
        Plasma major radius [m]
    A:
        Plasma aspect ratio
    B_0:
        Toroidal field at major radius [T]
    I_p:
        Plasma current [A]
    Returns
    -------
    Cylindrical safety factor
    Notes
    -----
    Sometimes also written with :math:`\\dfrac{2\\pi}{\\mu_{0}} = 5` and I_p in [MA]
    """
    a = R_0 / A
    return 2 * np.pi * a**2 * B_0 / (MU_0 * R_0 * I_p)