model.py

class Model(object):
    def add_placeholders(self):
        raise NotImplementedError("Each Model must re-implement this method.")

    def create_feed_dict(self, inputs_batch, labels_batch=None):
        raise NotImplementedError("Each Model must re-implement this method.")

    def add_prediction_op(self):
        raise NotImplementedError("Each Model must re-implement this method.")

    def add_loss_op(self, pred):
        raise NotImplementedError("Each Model must re-implement this method.")

    def add_training_op(self, loss):
        raise NotImplementedError("Each Model must re-implement this method.")

    def train_on_batch(self, sess, inputs_batch, labels_batch):
        feed = self.create_feed_dict(inputs_batch, labels_batch=labels_batch)
        _, loss = sess.run([self.train_op, self.loss], feed_dict=feed)
        return loss

    def predict_on_batch(self, sess, inputs_batch):
        feed = self.create_feed_dict(inputs_batch)
        predictions = sess.run(self.pred, feed_dict=feed)
        return predictions

    def build(self):
        self.add_placeholders()
        self.add_prediction_op()
        self.add_loss_op()
        self.add_training_op()