I was trying to find the syntax error in my code. I'm doing a 8 puzzle problem for my AI class. Would appreciate it greatly. Thank You.

import random from collections import deque namedtuple from operator import eq

class Puzzle (namedtuple("PuzzleField", ["board", "width", "zero_at"])): """ A class representing an '8 puzzle'. -'board' should be a list of list with integer entries 0. e.g. [[A,B,C], [D,E,F],[G,H,I]] """ __slots__=() def __new__(cls, board, width, zero_at=None): if zero_at is None: zero_at=board.index(0) return super().__new__(cls, board, width, zero_at) def solved (self): return all def actions(self): at= self.zero_at if at >=self.width: yield self.move(at-self.width) if at+ self.width yield self._move(at + self.width) if at self.width: yield self._move(at-1) def fhuffle (self): """ Makes a new puzzle with 700 different moves """ puzzle = self for _ in range(700): puzzle=random.choice return puzzle

def _move(self, to): """ Return a new puzzle where 'zero_at' and 'to' tiles have been swapped. NOTE: all moves should be 'actions' that have been executed """ a, b = min(self.zero_at, to), max(self.zero_at, to) board = list(self.board) board[a], board[b] = board[b], board[a] return Puzzle(tuple(board), self.width, to) def pprint (self): for i in range(0, len(self.board), self.width): print(self.board[i:i+self.width])

class Node(namedtuple("NodeFields", ["puzzle", "parent"])): """ A class representing an Solver node - 'puzzle' is a Puzzle instance - 'parent' is the preceding node generated by the solver, if any - 'action' is the action taken to produce puzzle, if any """ __slots__ = () def __new__(cls, puzzle, parent=None): return super().__new__(cls, puzzle, parent) @property def action (self): if self.parent is None: return None

diff_to_action = { +self.puzzle.width: 'D', -self.puzzle.width: 'U', +1: 'R', -1: 'L', }

return diff_to_action[self.puzzle.zero_at - self.parent.puzzle.zero_at] def path (node): """ Reconstruct a path from to the root 'parent' """ seen = [] while node is not None: seen.append(node) node = node.parent return reversed(seen)

def solve (start): """ Perform breadth first search and return a path to the solution, if it exists (otherwise None). """ queue = deque([Node(start)]) seen = {start} if start.solved(): return path(Node(start, None)) while queue: node = queue.pop() for move in node.puzzle.actions(): if move.board not in seen: if move.solved(): return path(Node(move, node)) queue.appendleft(Node(move, node)) seen.add(move.board) def main(): board = A,B,C, D,E,F, G,H,I puzzle = Puzzle(board, C) puzzle = puzzle.shuffle() p = solve(puzzle) for node in p: print(node.action) node.puzzle.pprint() print() if __name__ == "__main__": main()