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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def calculate_tree_length(self):
 """ Walks the tree and calculate the tree length """

        tree_length = 0

        for ext in self.tree:
            tree_length += len(ext) + 2

            for relpath in self.tree[ext]:
                tree_length += len(relpath) + 2

                for filename in self.tree[ext][relpath]:
                    tree_length += len(filename) + 1 + 18

        return tree_length + 1