                      exit()
  
          except KeyboardInterrupt:
              try:
                  model.save_weights()
              except KeyboardInterrupt:
                  print('Saving model weights has been cancelled!')
 
</s> remove                 for name, image in self.preview_buffer.items():
                    cv2.imshow(name, image)

                key = cv2.waitKey(1000)
                if key == ord('\n') or key == ord('\r'):
 </s> add                 try:
                    for name, image in self.preview_buffer.items():
                        cv2.imshow(name, image)

                    key = cv2.waitKey(1000)
                    if key == ord('\n') or key == ord('\r'):
                        break
                    if key == ord('s'):
                        self.save_now = True
                except KeyboardInterrupt: </s> remove                 trainer.train_one_step(epoch, self.show if save_iteration else None)
 </s> add                 trainer.train_one_step(epoch, self.show if (save_iteration or self.save_now) else None) </s> remove         trainer = PluginLoader.get_trainer(variant)(model, images_A, images_B)
 </s> add         trainer = PluginLoader.get_trainer(self.arguments.trainer)(model,
                                                                   images_A,
                                                                   images_B,
                                                                   batch_size=self.arguments.batch_size) </s> remove         model = PluginLoader.get_model(variant)(self.arguments.model_dir)
 </s> add         model = PluginLoader.get_model(self.arguments.trainer)(self.arguments.model_dir) </s> remove     BATCH_SIZE = 64

    def __init__(self, model, fn_A, fn_B):
 </s> add     def __init__(self, model, fn_A, fn_B, batch_size=64):
        self.batch_size = batch_size

                if self.save_now:
                    model.save_weights()
                    self.save_now = False

                      exit()
  
                if self.save_now:
                    model.save_weights()
                    self.save_now = False

          except KeyboardInterrupt:
              try:
                  model.save_weights()
              except KeyboardInterrupt:
                  print('Saving model weights has been cancelled!')
keep add keep keep keep keep keep
 added batch-size cli argumet.
neatened up train.py and added LowMem trainer option.
Added save_now/show key to preview. 
scripts/train.py