#! python3

planets = [ 'earth', 'mars' ]

ear = r"C:\Users\User\Desktop\python files\Earth.gif"
mar = r"C:\Users\User\Desktop\python files\Mars.gif"

GIF = [ ear, mar ]

def main():
        print('Enter the name of the planet you like to see')
        inpuT = input()

        while inpuT not in planets:
                print('Enter the name of the planet you like to see')
                inpuT = input()

        a = planets.index(inpuT)

        import tkinter as tk
        from tkinter import PhotoImage                                              
        from tkinter import Label
        import threading
        from PIL import Image, ImageTk

#-----------------------------------------------------------
        class AnimatedGIF(Label, object):
            def __init__(self, master, path, forever=True):
                self._master = master
                self._loc = 0
                self._forever = forever

                self._is_running = False

                im = Image.open(path)
                self._frames = []
                i = 0
                try:
                    while True:
                        photoframe = ImageTk.PhotoImage(im.copy().convert('RGBA'))
                        self._frames.append(photoframe)

                        i += 1
                        im.seek(i)
                except EOFError: pass

                self._last_index = len(self._frames) - 1

                try:
                    self._delay = im.info['duration']
                except:
                    self._delay = 100

                super(AnimatedGIF, self).__init__(master, image=self._frames[0])

            def start_animation(self, frame=None):
                if self._is_running: return

                if frame is not None:
                    self._loc = 0
                    self.configure(image=self._frames[frame])

                self._master.after(self._delay, self._animate_GIF)

            def _animate_GIF(self):
                self._loc += 1
                self.configure(image=self._frames[self._loc])

                if self._loc == self._last_index:
                    if self._forever:
                        self._loc = 0
                        self._callback_id = self._master.after(self._delay, self._animate_GIF)

                else:
                    self._callback_id = self._master.after(100, self._animate_GIF)   

            def pack(self, start_animation=True, **kwargs):
                if start_animation:
                    self.start_animation()

                super(AnimatedGIF, self).pack(**kwargs)


        class Worker(threading.Thread):                    
                def run(self):
                        global root                        
                        root = tk.Tk()                     
                        win = AnimatedGIF(root, GIF[a])    
                        win.pack()                         
                        root.mainloop()

        w = Worker()                                       
        w.start()
        inpuT_1 = input()
        if inpuT_1 == 'ok':
                root.quit()

while True:
        main()

Error:
Exception in thread Thread-2:
Traceback (most recent call last):
  File "C:\Users\User\AppData\Local\Programs\Python\Python37-32\lib\threading.py", line 917, in _bootstrap_inner
    self.run()
  File "C:\Python33\vezbe\GIF-treding problem 1.py", line 111, in run
    z.put(AnimatedGIF(root, alt[a]))
  File "C:\Python33\vezbe\GIF-treding problem 1.py", line 60, in __init__
    photoframe = ImageTk.PhotoImage(im.copy().convert('RGBA'))
  File "C:\Users\User\AppData\Local\Programs\Python\Python37-32\lib\site-packages\PIL\ImageTk.py", line 117, in __init__
    self.__photo = tkinter.PhotoImage(**kw)
  File "C:\Users\User\AppData\Local\Programs\Python\Python37-32\lib\tkinter\__init__.py", line 3545, in __init__
    Image.__init__(self, 'photo', name, cnf, master, **kw)
  File "C:\Users\User\AppData\Local\Programs\Python\Python37-32\lib\tkinter\__init__.py", line 3501, in __init__
    self.tk.call(('image', 'create', imgtype, name,) + options)
RuntimeError: main thread is not in main loop