ValueError:要解包的值太多（应为2），listcomp

Question

一直在尝试学习python，因此使用了一个预先制作的扫雷器，练习的是制作一个类的一些函数。但我似乎发现了一个错误：

line 66, in <listcomp>
    values = [grid[r][c] for r,c in self.getneighbors(grid, rowno, colno)]
ValueError: too many values to unpack (expected 2)

我不知道该怎么修，试过了。但我不知道该怎么办。希望我能得到一些帮助/提示。谢谢您！你知道吗

import string
import random


gridsize = int(input('SIZE:'))
numberofmines = int(input('MINES:'))

def setupgrid(gridsize,start,numberofmines):
    grid = [['0' for i in range(gridsize)] for i in range(gridsize)]
    mines = generatemines(grid,start,numberofmines)
    p = omringande(grid)
    p.getnumbers(grid)
    return (grid,mines)

def showgrid(grid):
    gridsize = len(grid)
    horizontal = '   '+4*gridsize*'-'+'-'
    # Print top column letters
    toplabel = ' :)  '
    for i in string.ascii_lowercase[:gridsize]:
        toplabel = toplabel+i+'   '
    print (toplabel,'\n',horizontal)
    # Print left row numbers
    for idx,i in enumerate(grid):
        row = '{0:2} |'.format(idx+1)
        for j in i:
            row = row+' '+j+' |'
        print (row+'\n'+horizontal)
    print ('')

def getrandomcell(grid):
    gridsize = len(grid)
    a = random.randint(0,gridsize-1)
    b = random.randint(0,gridsize-1)
    return (a,b)


class omringande(object):
    def __init__(self,grid):
        self.grid = grid

    def getneighbors(self,grid,rowno,colno):
        gridsize = len(grid)
        row = grid[rowno]
        column = grid[rowno][colno]

        neighbors = []

        for i in range(-1,2):
            for j in range(-1,2):
                if i == 0 and j == 0: continue
                elif -1<rowno+i<gridsize and -1<colno+j<gridsize:
                    neighbors.append((rowno+i,colno+j))

        return (row,column)

    def getnumbers(self,grid):
        gridsize = len(grid)
        for rowno,row in enumerate(grid):
            for colno,col in enumerate(row):
                if col!='X':
                    # Gets the values of the neighbors
                    values = [grid[r][c] for r,c in self.getneighbors(grid, rowno, colno)]

                    # Counts how many are mines
                    grid[rowno][colno] = str(values.count('X'))


# Generate mines
def generatemines(grid,start,numberofmines):
    gridsize = len(grid)
    mines = []
    for i in range(numberofmines):
        cell = getrandomcell(grid)
        while cell==(start[0],start[1]) or cell in mines:
            cell = getrandomcell(grid)
        mines.append(cell)

    for i,j in mines: grid[i][j] = 'X'
    return mines


def showcells(grid,currgrid,rowno,colno):
    # Exit function if the cell was already shown
    if currgrid[rowno][colno]!=' ':
        return

    # Show current cell
    currgrid[rowno][colno] = grid[rowno][colno]

    # Get the neighbors if the cell is empty
    if grid[rowno][colno] == '0':
        for r,c in omringande.getneighbors(grid,rowno,colno):
            # Repeat function for each neighbor that doesn't have a flag
            if currgrid[r][c] != 'F':
                showcells(grid,currgrid,r,c)

def playagain():
    choice = input('Play again? (y/n): ')
    return choice.lower() == 'y'

def playgame():

    currgrid = [[' ' for i in range(gridsize)] for i in range(gridsize)]
    showgrid(currgrid)
    grid = []
    flags = []
    helpmessage = "Type the column followed by the row (eg. a5).\nTo put or remove a flag, add 'f' to the cell (eg. a5f)\n"
    print (helpmessage)

    while True:
        while True:
            lastcell = str(input('Enter the cell ({} mines left): '.format(numberofmines-len(flags))))
            print ('\n\n')
            flag = False
            try:
                if lastcell[2] == 'f': flag = True
            except IndexError: pass

            try:
                if lastcell == 'help':
                    print (helpmessage)
                else:
                    lastcell = (int(lastcell[1])-1,string.ascii_lowercase.index(lastcell[0]))
                    break
            except (IndexError,ValueError):
                showgrid(currgrid)
                print ("Invalid cell.",helpmessage)

        if len(grid)==0:
            grid,mines = setupgrid(gridsize,lastcell,numberofmines)
        rowno,colno = lastcell

        if flag:
            # Add a flag if the cell is empty
            if currgrid[rowno][colno]==' ':
                currgrid[rowno][colno] = 'F'
                flags.append((rowno,colno))
            # Remove the flag if there is one
            elif currgrid[rowno][colno]=='F':
                currgrid[rowno][colno] = ' '
                flags.remove((rowno,colno))
            else: print ('Cannot put a flag there')

        else:
            # If there is a flag there, show a message
            if (rowno,colno) in flags:
                print ('There is a flag there')
            else:
                if grid[rowno][colno] == 'X':
                    print ('Game Over\n')
                    showgrid(grid)
                    if playagain(): playgame()
                    else: exit()
                else:
                    showcells(grid,currgrid,rowno,colno)

        showgrid(currgrid)

        if set(flags)==set(mines):
            print ('You Win')
            if playagain(): playgame()
            else: exit()

playgame()

当玩家应该移动的时候，我总是得到错误。尝试使用“.items”（在其他论坛中提到），但没有成功。你知道吗