Помогите с кодом python tkinter, точка на калькуляторе

 import tkinter as tk 
 
class Calculator: 
    def __init__(self, root): 
        self.root = root 
        self.root.title("Calculator") 
        self.expression = "" 
        self.input_text = tk.StringVar() 
        self.create_widgets() 
 
    def create_widgets(self): 
        input_frame = tk.Frame(self.root, width=312, height=50, bd=0, highlightbackground="black", highlightcolor="black", highlightthickness=1) 
        input_frame.pack(side=tk.TOP) 
 
        input_field = tk.Entry(input_frame, font=('arial', 18, 'bold'), textvariable=self.input_text, width=50, bg="#eee", bd=0, justify=tk.RIGHT) 
        input_field.grid(row=0, column=0) 
        input_field.pack(ipady=10) 
 
        buttons_frame = tk.Frame(self.root, width=312, height=272.5, bg="grey") 
        buttons_frame.pack() 
 
        # Row 1 
        self.create_button(buttons_frame, "7", 1, 0) 
        self.create_button(buttons_frame, "8", 1, 1) 
        self.create_button(buttons_frame, "9", 1, 2) 
        self.create_button(buttons_frame, "/", 1, 3) 
 
        # Row 2 
        self.create_button(buttons_frame, "4", 2, 0) 
        self.create_button(buttons_frame, "5", 2, 1) 
        self.create_button(buttons_frame, "6", 2, 2) 
        self.create_button(buttons_frame, "*", 2, 3) 
 
        # Row 3 
        self.create_button(buttons_frame, "1", 3, 0) 
        self.create_button(buttons_frame, "2", 3, 1) 
        self.create_button(buttons_frame, "3", 3, 2) 
        self.create_button(buttons_frame, "-", 3, 3) 
 
        # Row 4 
        self.create_button(buttons_frame, "0", 4, 0) 
        self.create_button(buttons_frame, ".", 4, 1) 
        self.create_button(buttons_frame, "=", 4, 2) 
        self.create_button(buttons_frame, "+", 4, 3) 
 
        # Clear button 
        clear_button = tk.Button(buttons_frame, text="C", fg="black", width=32, height=3, bd=0, bg="#eee", cursor="hand2", command=self.clear) 
        clear_button.grid(row=5, column=0, columnspan=4) 
 
    def create_button(self, frame, text, row, col): 
        button = tk.Button(frame, text=text, fg="black", width=10, height=3, bd=0, bg="#fff", cursor="hand2", command=lambda: self.add_to_expression(text)) 
        button.grid(row=row, column=col, padx=1, pady=1) 
 
    def add_to_expression(self, value): 
        if value == ".": 
            # Only add dot if there is no dot in the current number segment 
            if self.expression and self.expression[-1].isdigit(): 
                parts = self.expression.split("+") + self.expression.split("-") + self.expression.split("*") + self.expression.split("/") 
                if "." not in parts[-1]: 
                    self.expression += value 
                    self.input_text.set(self.expression) 
        else: 
            self.expression += value 
            self.input_text.set(self.expression) 
 
    def clear(self): 
        self.expression = "" 
        self.input_text.set("") 
 
    def evaluate(self): 
        try: 
            result = str(eval(self.expression)) 
            self.expression = result 
            self.input_text.set(result) 
        except: 
            self.input_text.set("error") 
            self.expression = "" 
 
if __name__ == "__main__": 
    root = tk.Tk() 
    calculator = Calculator(root) 
    root.mainloop() 

 import tkinter as tk 
from typing import Callable 
 
 
class Calculator: 
    def __init__(self, master: tk.Tk): 
        self.master = master 
        self.master.title("Калькулятор") 
        self.result_var = tk.StringVar() 
        self.result_var.set("0") 
        self.current_number = "0" 
        self.last_operation = None 
        self.result = 0 
        self.setup_ui() 
 
    def setup_ui(self): 
        # Создание и размещение элементов интерфейса 
        tk.Entry(self.master, textvariable=self.result_var, justify="right").grid( 
            row=0, column=0, columnspan=4, sticky="nsew") 
 
        buttons = [ 
            '7', '8', '9', '/', 
            '4', '5', '6', '*', 
            '1', '2', '3', '-', 
            '0', '.', '=', '+' 
        ] 
 
        for i, button in enumerate(buttons): 
            row, col = divmod(i, 4) 
            tk.Button(self.master, text=button, command=lambda x=button: self.on_button_click( 
                x)).grid(row=row+1, column=col, sticky="nsew") 
 
        for i in range(5): 
            self.master.grid_rowconfigure(i, weight=1) 
        for i in range(4): 
            self.master.grid_columnconfigure(i, weight=1) 
 
    def on_button_click(self, button: str): 
        if button.isdigit(): 
            self.add_digit(button) 
        elif button == '.': 
            self.add_decimal_point() 
        elif button in {'+', '-', '*', '/'}: 
            self.add_operation(button) 
        elif button == '=': 
            self.calculate_result() 
 
    def add_digit(self, digit: str): 
        if self.current_number == "0": 
            self.current_number = digit 
        else: 
            self.current_number += digit 
        self.update_display() 
 
    def add_decimal_point(self): 
        if '.' not in self.current_number: 
            self.current_number += '.' 
            self.update_display() 
 
    def add_operation(self, operation: str): 
        self.calculate_result() 
        self.last_operation = operation 
        self.result = float(self.current_number) 
        self.current_number = "0" 
 
    def calculate_result(self): 
        if self.last_operation: 
            second_number = float(self.current_number) 
            operations = { 
                '+': lambda x, y: x + y, 
                '-': lambda x, y: x - y, 
                '*': lambda x, y: x * y, 
                '/': lambda x, y: x / y if y != 0 else float('inf') 
            } 
            self.result = operations[self.last_operation]( 
                self.result, second_number) 
            self.current_number = str(self.result) 
            self.last_operation = None 
        self.update_display() 
 
    def update_display(self): 
        self.result_var.set(self.current_number) 
 
 
if __name__ == "__main__": 
    root = tk.Tk() 
    calc = Calculator(root) 
    root.mainloop()