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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 traverse_nodes(self, node_set, depth=0):
 """BFS traversal of nodes that returns name traversal as large string. Args: node_set: Set of input nodes to begin traversal. depth: Current traversal depth for child node viewing. Returns: type: String containing tabbed traversal view. """


        tab = "  "
        result = list()
        for n in node_set:
            repr = (
                n
                if self.nodes[n]["type"] == "variable"
                else f"{n}{inspect.signature(self.nodes[n]['lambda_fn'])}"
            )

            result.append(f"{tab * depth}{repr}")
            result.extend(
                self.traverse_nodes(self.successors(n), depth=depth + 1)
            )
        return result