code: def find_recursive_dependency(self):
      
      nodes_on_path = []
  
      def helper(nodes):
        for node in nodes:
          cycle = node in nodes_on_path
          nodes_on_path.append(node)
          if cycle or helper(self.deps.get(node, [])):
            return True
          nodes_on_path.pop()
        return False
  
      helper(self.unordered)
      return nodes_on_path
docs: Return a list of nodes that have a recursive dependency.