Change os.mkdir() -> os.mkdirs()

* We might need to create directories recursively

train.py

@@ -88,7 +88,7 @@ def log_print(text, color=None, on_color=None, attrs=None):
 optimizer = torch.optim.SGD(params[8:], lr=lr, momentum=momentum, weight_decay=weight_decay)
 
 if not os.path.exists(output_dir):
- os.mkdir(output_dir)
+ os.makedirs(output_dir)
 
 # tensorboad
 use_tensorboard = use_tensorboard and CrayonClient is not None