def forward(self, mol_trees, tree_vec):
        """
        The training procedure which computes the prediction loss given the
        ground truth tree
        """
        mol_tree_batch = batch(mol_trees)
        mol_tree_batch_lg = line_graph(
            mol_tree_batch, backtracking=False, shared=True
        )
        n_trees = len(mol_trees)

        return self.run(mol_tree_batch, mol_tree_batch_lg, n_trees, tree_vec)

        The training procedure which computes the prediction loss given the
        ground truth tree
        
examples/pytorch/jtnn/jtnn/jtnn_dec.py