def METHOD_NAME(a, b, R, df, ieps=1e-5, quadkwds=None, mvstkwds=None):
    """
    Probability of rectangular area of standard t distribution
    assumes mean is zero and R is correlation matrix
    Notes
    -----
    This function does not calculate the estimate of the combined error
    between the underlying multivariate normal probability calculations
    and the integration.
    """
    kwds = dict(args=(a, b, R, df), epsabs=1e-4, epsrel=1e-2, limit=150)
    if quadkwds is not None:
        kwds.update(quadkwds)
    lower, upper = chi.ppf([ieps, 1 - ieps], df)
    res, err = integrate.quad(funbgh2, lower, upper, **kwds)
    prob = res * bghfactor(df)
    return prob