Tkinter radiobutton IntVar Atributo error

Sé que cuando usas botones de radio necesitas configurar la variable en IntVar () si quieres usar un número. Desafortunadamente, el código que estoy ejecutando a continuación viene con el siguiente error:

Traceback (most recent call last): File "F:/Analysis and Maths/PD diagnostic tool/Project files/PD Tool v2.py", line 49, in  v = IntVar() File "C:\Python34\lib\tkinter\__init__.py", line 354, in __init__ Variable.__init__(self, master, value, name) File "C:\Python34\lib\tkinter\__init__.py", line 236, in __init__ self._root = master._root() AttributeError: 'NoneType' object has no attribute '_root' 

¿Alguien sabe por qué este sería el caso? Lo que me gustaría hacer es cambiar la imagen que se carga en pygame usando los botones de radio

 v = IntVar() class Window(Frame): def __init__(self, master=None): # This defines the main window Frame.__init__(self, master) self.master = master self.init_window() def init_window(self): global v self.master.title("PD Tool") self.pack(fill = BOTH, expand = 1) # This packs the frame showImg(self) import_button = ttk.Button(self, text = "import", command = lambda: filename()).place(x = 10, y = 5) start_pygame_button = ttk.Button(self, text = "Start PD tool", command = lambda: start_pygame_window()).place(x = 10, y = 35) RadioButton1 = ttk.Radiobutton(self, text = "One", variable = v, value = 1).place(x = 10, y=220) RadioButton2 = ttk.Radiobutton(self, text = "Two", variable = v, value = 2).place(x = 10, y=310) RadioButton3 = ttk.Radiobutton(self, text = "Three", variable = v, value = 3).place(x = 10, y=410) RadioButton4 = ttk.Radiobutton(self, text = "Four", variable = v, value = 4).place(x = 10, y=510) RadioButton5 = ttk.Radiobutton(self, text = "Five", variable = v, value = 5).place(x = 10, y=600) RadioButton6 = ttk.Radiobutton(self, text = "Six", variable = v, value = 6).place(x = 10, y=700) def active_image(): global file_path if v == 1: file_path = "F:\Analysis and Maths\PD diagnostic tool\Images\one.png" print(v) elif v == 2: file_path = "F:\Analysis and Maths\PD diagnostic tool\Images\wo.png" print(file_path) elif v == 3: file_path = "F:\Analysis and Maths\PD diagnostic tool\Images\hree.png" elif v == 4: file_path = "F:\Analysis and Maths\PD diagnostic tool\Images\our.png" elif v == 5: file_path = "F:\Analysis and Maths\PD diagnostic tool\Images\ive.png" elif v == 6: file_path = "F:\Analysis and Maths\PD diagnostic tool\Images\six.png" else: file_path = "F:\Analysis and Maths\PD diagnostic tool\Images\one.png" active_image_loaded = pygame.image.load(file_path) gameDisplay.blit(active_image_loaded,(0,0)) 

IntVar crear el widget raíz antes de crear el objeto IntVar .

Ajuste el código para crear un widget de raíz primero:

 root = Tk() # <--- v = IntVar()