@classmethod
def print_convergence(cls, progress, true):
    """Print the progress of a model over each iteration.

        -- {progress} should be a list of {scipy.stats.norm} distributions,
           such as the one returned by {predict_from_trace}.
        -- {true} should be the true, final converged value, which is used
           in the output for illustrating the convergence progress.
        """
    print(' %2s %6s  %6s  %7s  %9s  %6s' % ('It', 'PDF', 'CDF', 'Error',
        'PostMean', 'Stdev'))
    for i, d in enumerate(progress):
        print('%2d: %6.4f  %6.4f  %7.4f  %9.4f  %6.4f' % (i, d.pdf(true), d
            .cdf(true), (d.mean() - true) / true, d.mean(), d.std()))
