* return any([item node for def depth_first_graph_search(problem): "Search deepest nodes in the search tree first." #create a frontiers queue # create a node for initial state and append it to frontiers # go through frontiers queue # create a set to keep track of reached/expanded states # get the node from queue - #check if it is goal # if yes, return the node item in self.items]) # expand the node # add node's state to reached/expanded states set return failure I #make sure child's state is not reached AND child node is not in the queue