Fixed Error - Checkpoint filename is invalid on Windows

This commit fixed the error (Checkpoint filename is invalid on Windows) using strftime replacing the original one.

models.py

@@ -1136,16 +1136,20 @@ def train(
 
 def save_model(model, model_name, dataset_name, **kwargs):
     model_dir = "./checkpoints/" + model_name + "/" + dataset_name + "/"
+    """
+    Using strftime in case it triggers exceptions on windows 10 system
+    """
+    time_str = datetime.datetime.now().strftime('%Y_%m_%d_%H_%M_%S')
     if not os.path.isdir(model_dir):
         os.makedirs(model_dir, exist_ok=True)
     if isinstance(model, torch.nn.Module):
-        filename = str(datetime.datetime.now()) + "_epoch{epoch}_{metric:.2f}".format(
+        filename = time_str + "_epoch{epoch}_{metric:.2f}".format(
             **kwargs
         )
         tqdm.write("Saving neural network weights in {}".format(filename))
         torch.save(model.state_dict(), model_dir + filename + ".pth")
     else:
-        filename = str(datetime.datetime.now())
+        filename = time_str
         tqdm.write("Saving model params in {}".format(filename))
         joblib.dump(model, model_dir + filename + ".pkl")