Python 如何修复此错误消息？

这是我按下返回键时收到的错误消息。我不知道它是什么意思，也不知道如何修复它。

请看，您应该将案例缩小到最简单的示例。此代码中还有许多其他错误使其无法使用。第一个sum1不是全局的。在第一类中，sum1应替换为self。在第二个类中，您没有将sum1作为参数传递，因此无法使用它。

from tkinter import *

class Countinator():
    def __init__(self, parent):
        self.total = 0
        self.current = StringVar()
        self.new_num = True
        self.parent=parent
        self.operator_pending = False                                                                           #Runs when the class Countinator is called. Sets all the variables to begin with
        self.equated = False
        self.entry= Entry(parent, justify=RIGHT)
        self.entry.grid(row = 0, column = 0, columnspan = 4, pady = 5)
        self.entry.insert(0, "0")

        self.parent.bind("0",lambda event : self.num_press(self, "0"))
        self.parent.bind("1",lambda event : self.num_press(self, "1"))
        self.parent.bind("2",lambda event : self.num_press(self, "2"))
        self.parent.bind("3",lambda event : self.num_press(self, "3"))
        self.parent.bind("4",lambda event : self.num_press(self, "4"))
        self.parent.bind("5",lambda event : self.num_press(self, "5"))
        self.parent.bind("6",lambda event : self.num_press(self, "6"))
        self.parent.bind("7",lambda event : self.num_press(self, "7"))
        self.parent.bind("8",lambda event : self.num_press(self, "8"))
        self.parent.bind("9",lambda event : self.num_press(self, "9"))
        self.parent.bind("+",lambda event : sum1.operation("but_addition"))
        self.parent.bind("-",lambda event : sum1.operation("but_minus"))
        self.parent.bind("*",lambda event : sum1.operation("but_multiply"))
        self.parent.bind("/",lambda event : sum1.operation("but_divide"))
        self.parent.bind(".",lambda event : sum1.mouse_press("."))
        self.parent.bind("<Return>", sum1.calculate_total2)
        self.parent.bind("<Delete>", lambda event : sum1.clear2)
        self.parent.bind("<BackSpace>", lambda event : sum1.backspace2)


    def num_press(self, event, num):
        self.equated = False
        temporary = self.entry.get()
        temporary2 = num
        print(self.entry.get())
        if self.new_num:
            self.current = temporary2                                                                           #Looks for when a number is pressed
            self.new_num = False
        else:
            if temporary2 == '.':
                if temporary2 in temporary:
                    return temporary
            self.current = temporary + temporary2
        self.display(self.current)

    def mouse_press(self, num):
        self.equated = False
        temporary = self.entry.get()
        temporary2 = str(num)
        if self.new_num:
            self.current = temporary2                                                                           #Looks for when a number is pressed
            self.new_num = False
        else:
            if temporary2 == '.':
                if temporary2 in temporary:
                    return
            self.current = temporary + temporary2
        self.display(self.current)

    def calculate_total(self):
        self.equated = True
        self.current = float(self.current)
        if self.operator_pending == True:                                                                       #Called when the equals key is pressed
            self.do_sum()
        else:
            self.total = float(self.entry.get())

    def calculate_total2(self, event):
        self.equated = True
        self.current = float(self.current)
        if self.operator_pending == True:                                                                       #Called when the equals key is pressed
            self.do_sum()
        else:
            self.total = float(self.entry.get())

    def display(self, value):
        self.entry.delete(0, END)                                                                               #Displays the numbers from the label
        self.entry.insert(0, value)

    def do_sum(self):
        if self.operator == "but_addition":
            self.total += self.current
        if self.operator == "but_minus":
            self.total -= self.current
        if self.operator == "but_multiply":                                                                         #Does the multiply, addition, subtraction and division
            self.total *= self.current
        if self.operator == "but_divide":
            self.total /= self.current
        self.new_num = True
        self.operator_pending = False
        self.display(self.total)

    def operation(self, operator):
        self.current = float(self.current)
        if self.operator_pending:
            self.do_sum()
        elif not self.equated:
            self.total = self.current
        self.new_num = True
        self.operator_pending = True
        self.operator = operator
        self.eq = False

    def backspace(self):
        print("backspace mouse")

    def backspace2(self, event):
        print("backspace key")

    def clear(self):
        self.equated = False
        self.current = "0"                                                                                      #Backspace only one character from the label
        self.display(0)
        self.new_num = True

    def clear2(self, event):
        self.equated = False
        self.current = "0"                                                                                      #Backspace only one character from the label
        self.display(0)
        self.new_num = True



class GUI:
    def __init__(self, parent):
        self.numbers=["7","8","9","4","5","6","1","2","3","0"]
        self.parent=parent
        i=0
        self.buttons = []
        for rows in range(1,4):
            for columns in range(3):                                                                            #Create the 1-9 buttons and binds them to the button
                self.buttons.append(Button( text = self.numbers[i], relief=RIDGE, padx=24, pady=24))
                self.buttons[i].grid(row = rows, column = columns, padx=2, pady=2)
                self.buttons[i]["command"] = lambda event = self.numbers[i]: sum1.mouse_press(event)
                i += 1

        self.buttons.append(Button(parent, text = self.numbers[9], relief=RIDGE, padx=24, pady=24))
        self.buttons[9].grid(padx=2, pady=2,row=5, column=0,columnspan=2, sticky=W+E)
        self.buttons[9]["command"]=lambda event=self.numbers[9]: sum1.mouse_press(0)
        self.buttons[0].grid(row=2, column=0, padx=2, pady=2)
        self.buttons[1].grid(row=2, column=1, padx=2, pady=2)
        self.buttons[2].grid(row=2, column=2, padx=2, pady=2)
        self.buttons[3].grid(row=3, column=0, padx=2, pady=2)
        self.buttons[4].grid(row=3, column=1, padx=2, pady=2)
        self.buttons[5].grid(row=3, column=2, padx=2, pady=2)                                                   #Sets the buttons to a set place in the grid
        self.buttons[6].grid(row=4, column=0, padx=2, pady=2)
        self.buttons[7].grid(row=4, column=1, padx=2, pady=2)
        self.buttons[8].grid(row=4, column=2, padx=2, pady=2)

        but_multiply=Button(parent, text="*", relief=RIDGE, padx=24, pady=24)
        but_multiply.grid(row=2, column=3, padx=2, pady=2)
        but_multiply["command"] = lambda: sum1.operation("but_multiply")

        but_divide=Button(parent, text="/", relief=RIDGE, padx=24, pady=24)
        but_divide.grid(row=2, column=4, padx=2, pady=2)
        but_divide["command"] = lambda: sum1.operation("but_divide")

        but_minus=Button(parent, text="-", height=6, relief=RIDGE, padx=24, pady=24)
        but_minus.grid(row=3, column=3, rowspan=2, padx=2, pady=2)
        but_minus["command"] = lambda: sum1.operation("but_minus")

        but_addition=Button(parent, height=6, text="+", relief=RIDGE, padx=24, pady=24)
        but_addition.grid(row=3, column=4, rowspan=2, padx=2, pady=2)
        but_addition["command"] = lambda: sum1.operation("but_addition")

        but_equals=Button(parent, width=11, text="=", relief=RIDGE, padx=24, pady=24)                           #The special characters that get called when the keys are pressed
        but_equals.grid(row=5, column=3, padx=2, pady=2, columnspan=2)
        but_equals["command"] = sum1.calculate_total

        but_decimal=Button(parent, text=".", relief=RIDGE, padx=24, pady=24)
        but_decimal.grid(row=5, column=2, padx=2, pady=2)
        but_decimal["command"] = lambda: sum1.mouse_press(".")

        but_backspace=Button(parent, text="Backspace", relief=RIDGE, padx=13, pady=24, width=24)
        but_backspace.grid(row=1, column=2, padx=2, pady=2, columnspan=3)
        but_backspace["command"] = sum1.backspace

        but_clear=Button(parent, text="Clear", relief=RIDGE, padx=13, pady=24, width=14)
        but_clear.grid(row=1, column=0, padx=2, pady=2, columnspan=2)
        but_clear["command"] = sum1.clear

root=Tk()
sum1=Countinator(root)
calculator=Frame()
calculator.grid()

gui=GUI(root)
gui=Frame()
gui.grid()



root.title("Calculator")
root.mainloop()

Traceback (most recent call last):
  File "D:\12 Digi\Python\Portable Python 3.2.1.1\App\lib\tkinter\__init__.py", line 1399, in __call__
    return self.func(*args)
  File "D:\12 Digi\Python 2014\Calculator\Combined.py", line 86, in calculate_total2
    self.do_sum()
  File "D:\12 Digi\Python 2014\Calculator\Combined.py", line 105, in do_sum
    self.display(self.total)
  File "D:\12 Digi\Python 2014\Calculator\Combined.py", line 91, in display
    self.entry.delete(0, END)                                                                               #Displays the numbers from the label
  File "D:\12 Digi\Python\Portable Python 3.2.1.1\App\lib\tkinter\__init__.py", line 2372, in delete
    self.tk.call(self._w, 'delete', first, last)
_tkinter.TclError: invalid command name ".82911024"