title: How to fix "pickle_module.load(f, **pickle_load_args) _pickle.UnpicklingError: invalid load key, '<'" using YOLOv3?
body: <p>I am trying to train YOLOv3 using this repository with custom dataset</p>
  <p><a href="https://github.com/ultralytics/yolov3" rel="nofollow noreferrer">https://github.com/ultralytics/yolov3</a></p>
  <p>I used the weight that recommended in the readme yolov3-spp-ultralytics.pt</p>
  <p>When I train I get the following error:</p>
  <pre><code>Traceback (most recent call last):
    File &quot;yolov3/train.py&quot;, line 431, in &lt;module&gt;
      train(hyp)  # train normally
    File &quot;yolov3/train.py&quot;, line 119, in train
      ckpt = torch.load(weights, map_location=device)
    File &quot;/opt/conda/lib/python3.7/site-packages/torch/serialization.py&quot;, line 593, in load
      return _legacy_load(opened_file, map_location, pickle_module, **pickle_load_args)
    File &quot;/opt/conda/lib/python3.7/site-packages/torch/serialization.py&quot;, line 763, in _legacy_load
      magic_number = pickle_module.load(f, **pickle_load_args)
  _pickle.UnpicklingError: invalid load key, '&lt;'.
  </code></pre>
  <p>Any idea how Yolov3 pickles the file?</p>