您好，我最近開(kāi)始學(xué)習(xí) tkinter 并決定學(xué)習(xí)國(guó)際象棋棋盤游戲。下面是我的代碼：import tkinter as tkclass GameBoard(tk.Frame):    def __init__(self, parent, rows=8, columns=8, size=70, color1="white", color2="blue"):        '''size is the size of a square, in pixels'''        self.rows = rows        self.columns = columns        self.size = size        self.color1 = color1        self.color2 = color2        self.pieces = {}        canvas_width = columns * size        canvas_height = rows * size        tk.Frame.__init__(self, parent)        self.canvas = tk.Canvas(self, borderwidth=0, highlightthickness=0,                                width=canvas_width, height=canvas_height, background="bisque")        self.canvas.pack(side="top", fill="both", expand=True, padx=2, pady=2)root = tk.Tk()board = GameBoard(root)board.pack(side="top", fill="both", expand="true", padx=4, pady=4)black_rook_l = tk.PhotoImage(file=black_rook_img)black_rook_l = black_rook_l.subsample(2, 2)board.addpiece("black_rook_l", black_rook_l, 0,0)上面的代碼我是將一塊（黑車）添加到板上，它按預(yù)期工作。下面是輔助函數(shù)：def addpiece(self, name, image, row=0, column=0):    '''Add a piece to the playing board'''    self.canvas.create_image(0,0, image=image, tags=(name, "piece"), anchor="c")    self.placepiece(name, row, column)def placepiece(self, name, row, column):    '''Place a piece at the given row/column'''    self.pieces[name] = (row, column)    x0 = (column * self.size) + int(self.size/2)    y0 = (row * self.size) + int(self.size/2)    # print(name, x0, y0)    self.canvas.coords(name, x0, y0)但是當(dāng)我嘗試在 for 循環(huán)的幫助下放置 pawn 時(shí)出現(xiàn)問(wèn)題。下面是代碼：for i in range(8):    bname = tk.PhotoImage(file=black_pawn_img)    bname = bname.subsample(2, 2)    board.addpiece("black_pawn_"+str(i), bname, 1,i)root.mainloop()它只放置最后一個(gè) Pawn 塊。請(qǐng)建議/幫助我理解這個(gè)問(wèn)題。