I am trying to understand how backprop is achieved by the autograd engine. Learned that when new tensors are created it includes a grad_fn attribute that tells us about the operation that created it and it in turn has has next_functions that converys information about the parent node. But during backprop operations like matmul will require the input during forward propagation and are they exposed through some python functions.?? I understood that they are stored in some autograd metadata so that autgrad engine has access to how nodes are created in the forward pass. Is there a way to access this graph in python?