I wen through the function step by step in hopes of figuring out what’s going on as below
checkpoint = torch.load('vgg19.pth')
state_dict=checkpoint['state_dict']
temp_model = models.vgg19(pretrained=True)
temp_model.load_state_dict(state_dict, strict=True)

The error thrown is
RuntimeError                              Traceback (most recent call last)
<ipython-input-35-d8320f134783> in <module>
----> 1 temp_model.load_state_dict(state_dict, strict=True)

~/anaconda3/envs/deep-learning/lib/python3.6/site-packages/torch/nn/modules/module.py in load_state_dict(self, state_dict, strict)
    767         if len(error_msgs) > 0:
    768             raise RuntimeError('Error(s) in loading state_dict for {}:\n\t{}'.format(
--> 769                                self.__class__.__name__, "\n\t".join(error_msgs)))
    770 
    771     def _named_members(self, get_members_fn, prefix='', recurse=True):

RuntimeError: Error(s) in loading state_dict for VGG:
	Missing key(s) in state_dict: "classifier.0.weight", "classifier.0.bias", "classifier.3.weight", "classifier.3.bias", "classifier.6.weight", "classifier.6.bias". 
	Unexpected key(s) in state_dict: "classifier.fc1.weight", "classifier.fc1.bias", "classifier.fc2.weight", "classifier.fc2.bias".