human
What is a Python code to print '{}    {}    <->    {}    {}' given the following:
I wrote the below code

    (x, y, params) = model.get_training_model()
    y_ = tf.placeholder(tf.float32, [None, ((7 * len(common.CHARS)) + 1)])
    (digits_loss, presence_loss, loss) = get_loss(y, y_)
    train_step = tf.train.AdamOptimizer(learn_rate).minimize(loss)
    best = tf.argmax(tf.reshape(y[:, 1:], [(-1), 7, len(common.CHARS)]), 2)
    correct = tf.argmax(tf.reshape(y_[:, 1:], [(-1), 7, len(common.CHARS)]), 2)
    if (initial_weights is not None):
        assert (len(params) == len(initial_weights))
        assign_ops = [w.assign(v) for (w, v) in zip(params, initial_weights)]
    init = tf.initialize_all_variables()
    def vec_to_plate(v):
        return ''.join((common.CHARS[i] for i in v))
    def do_report():
        r = sess.run([best, correct, tf.greater(y[:, 0], 0), y_[:, 0], digits_loss, presence_loss, loss], feed_dict={x: test_xs, y_: test_ys})
        num_correct = numpy.sum(numpy.logical_or(numpy.all((r[0] == r[1]), axis=1), numpy.logical_and((r[2] < 0.5), (r[3] < 0.5))))
        r_short = (r[0][:190], r[1][:190], r[2][:190], r[3][:190])
        for (b, c, pb, pc) in zip(*r_short):
            print '{}    {}    <->    {}    {}'.format(vec_to_plate(c), pc, vec_to_plate(b), float(pb))
        num_p_correct = numpy.sum((r[2] == r[3]))
        print 'B{:3d}    {:2.02f}%    {:02.02f}%    loss:    {}    (digits:    {},    presence:    {})    |{}|'.format(batch_idx, ((100.0 * num_correct) / len(r[0])), ((100.0 * num_p_correct) / len(r[2])), r[6], r[4], r[5], ''.join(('X    '[(numpy.array_equal(b, c) or ((not pb) and (not pc)))] for (b, c, pb, pc) in zip(*r_short))))
    def do_batch():
        sess.run(train_step, feed_dict={x: batch_xs, y_: batch_ys})
        if ((batch_idx % report_steps) == 0):
            do_report()
    gpu_options = tf.GPUOptions(per_process_gpu_memory_fraction=0.95)
    with tf.Session(config=tf.ConfigProto(gpu_options=gpu_options)) as sess:
        sess.run(init)
        if (initial_weights is not None):
            sess.run(assign_ops)
        (test_xs, test_ys) =...

What's a good function header?
assistant
#Here is Python code to print '{}    {}    <->    {}    {}'.

def train(learn_rate, report_steps, batch_size, initial_weights=None):