Python tkinter ile basit hesap makinesi yapımı

try:
 import Tkinter as tk.
except ImportError:
 import tkinter as tk.

class Calculator:
 def __init__(self):
 self._stack = []
 self._valid = [
 '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '-', '*', '/'
 ]

 def add(self, text):
 if text not in self._valid:
 return ''.
 self._stack.append(text)
 return text.

 def get(self):
 return ''.join(self._stack)

 def evaluate(self):
 try:
 result = eval(self.get())
 except Exception as ex:
 result = ex.

 return str(result)

 def reset(self):
 self._stack = []

class Window(tk.Tk):
 is_reset = True.

 def __init__(self):
 super().__init__()

 self.calculator = Calculator()

 self.geometry(self.get_geometry())
 self.resizable(False, False)
 self.title("Hesap Makinesi CoderMoko")

 self.result = tk.StringVar()
 self.ent_result = tk.Entry(self, textvariable=self.result)
 self.ent_result.place(relx=0.031, rely=0.031, relheight=0.266, relwidth=0.953)
 self.ent_result.configure(background="white", font="TkFixedFont", justify='right')

 self.btn_7 = tk.Button(self)
 self.btn_7.place(relx=0.031, rely=0.344, height=41, width=61)
 self.btn_7.configure(text='7')

 self.btn_8 = tk.Button(self)
 self.btn_8.place(relx=0.281, rely=0.344, height=41, width=61)
 self.btn_8.configure(text='8')

 self.btn_9 = tk.Button(self)
 self.btn_9.place(relx=0.531, rely=0.344, height=41, width=61)
 self.btn_9.configure(text='9')

 self.btn_add = tk.Button(self)
 self.btn_add.place(relx=0.781, rely=0.344, height=41, width=61)
 self.btn_add.configure(text='+')

 self.btn_4 = tk.Button(self)
 self.btn_4.place(relx=0.031, rely=0.5, height=41, width=61)
 self.btn_4.configure(text='4')

 self.btn_5 = tk.Button(self)
 self.btn_5.place(relx=0.281, rely=0.5, height=41, width=61)
 self.btn_5.configure(text='5')

 self.btn_6 = tk.Button(self)
 self.btn_6.place(relx=0.531, rely=0.5, height=41, width=61)
 self.btn_6.configure(text='6')

 self.btn_sub = tk.Button(self)
 self.btn_sub.place(relx=0.781, rely=0.5, height=41, width=61)
 self.btn_sub.configure(text='-')

 self.btn_2 = tk.Button(self)
 self.btn_2.place(relx=0.281, rely=0.656, height=41, width=61)
 self.btn_2.configure(text='2')

 self.btn_1 = tk.Button(self)
 self.btn_1.place(relx=0.031, rely=0.656, height=41, width=61)
 self.btn_1.configure(text='1')

 self.btn_3 = tk.Button(self)
 self.btn_3.place(relx=0.531, rely=0.656, height=41, width=61)
 self.btn_3.configure(text='3')

 self.btn_mul = tk.Button(self)
 self.btn_mul.place(relx=0.781, rely=0.656, height=41, width=61)
 self.btn_mul.configure(text='x')

 self.btn_c = tk.Button(self)
 self.btn_c.place(relx=0.031, rely=0.813, height=41, width=61)
 self.btn_c.configure(text='C', activebackground='#FFF')

 self.btn_0 = tk.Button(self)
 self.btn_0.place(relx=0.281, rely=0.813, height=41, width=61)
 self.btn_0.configure(text='0')

 self.btn_eq = tk.Button(self)
 self.btn_eq.place(relx=0.531, rely=0.813, height=41, width=61)
 self.btn_eq.configure(text='=', activebackground='#456')

 self.btn_div = tk.Button(self)
 self.btn_div.place(relx=0.781, rely=0.813, height=41, width=61)
 self.btn_div.configure(text='/')

 self.init_events()

 def init_events(self):
 # button events.
 self.btn_0.bind('<Button-1>', func=lambda event: self.key_clicked('0'))
 self.btn_1.bind('<Button-1>', func=lambda event: self.key_clicked('1'))
 self.btn_2.bind('<Button-1>', func=lambda event: self.key_clicked('2'))
 self.btn_3.bind('<Button-1>', func=lambda event: self.key_clicked('3'))
 self.btn_4.bind('<Button-1>', func=lambda event: self.key_clicked('4'))
 self.btn_5.bind('<Button-1>', func=lambda event: self.key_clicked('5'))
 self.btn_6.bind('<Button-1>', func=lambda event: self.key_clicked('6'))
 self.btn_7.bind('<Button-1>', func=lambda event: self.key_clicked('7'))
 self.btn_8.bind('<Button-1>', func=lambda event: self.key_clicked('8'))
 self.btn_9.bind('<Button-1>', func=lambda event: self.key_clicked('9'))

 # operation events.
 self.btn_add.bind('<Button-1>', func=lambda event: self.key_clicked('+'))
 self.btn_sub.bind('<Button-1>', func=lambda event: self.key_clicked('-'))
 self.btn_mul.bind('<Button-1>', func=lambda event: self.key_clicked('*'))
 self.btn_div.bind('<Button-1>', func=lambda event: self.key_clicked('/'))
 self.btn_c.bind('<Button-1>', func=lambda event: self.clear_clicked())
 self.btn_eq.bind('<Button-1>', func=lambda event: self.enter_clicked())

 # global events.
 self.bind('<Return>', func=lambda event: self.enter_clicked())
 self.bind('<Key>', func=lambda event: self.key_clicked(event.char))

 def key_clicked(self, key):
 if self.is_reset:
 self.result.set('')
 self.is_reset = False.

 self.result.set(self.result.get() + self.calculator.add(key))

 def enter_clicked(self):
 self.result.set(self.result.get() + '=' + self.calculator.evaluate())
 self.calculator.reset()
 self.is_reset = True.

 def clear_clicked(self):
 self.result.set('')
 self.calculator.reset()

 def get_geometry(self):
 width = height = 320.
 x = (self.winfo_screenwidth() // 2) - (width // 2)
 y = (self.winfo_screenheight() // 2) - (height // 2)
 geometry = '{}x{}+{}+{}'.format(width, height, x, y)
 return geometry.

if __name__ == '__main__':
 window = Window()
 window.mainloop()