import tensorflow as tf

    
    loss_summary = tf.summary.scalar('Loss', cross_entropy)
    acc_summary = tf.summary.scalar('Accuracy', accuracy)

    # summaries for TensorBoard visualisation
    validation_summary = tf.summary.merge([img_summary, acc_summary])
    training_summary = tf.summary.merge([img_summary, loss_summary])
    test_summary = tf.summary.merge([img_summary, acc_summary])

    # saver for checkpoints
    saver = tf.train.Saver(tf.global_variables(), max_to_keep=1)

