Photo Image Error

Hi. I love this project, but I sometimes receive these errors upon closing a window containing this widget. I experimented a bit, but I couldn't find a pattern for when it happens. It looks like it's trying to update the images and when you close the window right while the update happens, you get this error. But I could be wrong. It was never harmful anyways. It's just a mysterious text in the console, but it causes no problems. Still, I would like to find a way to remove/avoid this error. Can you give me some insight into it?

Exception in thread Thread-1 (pre_cache):
Traceback (most recent call last):
  File "/usr/lib/python3.10/threading.py", line 1009, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.10/threading.py", line 946, in run
    self._target(*self._args, **self._kwargs)
  File "/home/milan/.local/lib/python3.10/site-packages/tkintermapview/map_widget.py", line 278, in pre_cache
    self.request_image(zoom, x, self.pre_cache_position[1] + radius, db_cursor=db_cursor)
  File "/home/milan/.local/lib/python3.10/site-packages/tkintermapview/map_widget.py", line 348, in request_image
    image_tk = ImageTk.PhotoImage(image)
  File "/usr/lib/python3.10/site-packages/PIL/ImageTk.py", line 112, in __init__
    self.__photo = tkinter.PhotoImage(**kw)
  File "/usr/lib/python3.10/tkinter/__init__.py", line 4093, in __init__
    Image.__init__(self, 'photo', name, cnf, master, **kw)
  File "/usr/lib/python3.10/tkinter/__init__.py", line 4026, in __init__
    master = _get_default_root('create image')
  File "/usr/lib/python3.10/tkinter/__init__.py", line 297, in _get_default_root
    raise RuntimeError(f"Too early to {what}: no default root window")
RuntimeError: Too early to create image: no default root window
Exception ignored in: <function PhotoImage.__del__ at 0x7fa69afba5f0>
Traceback (most recent call last):
  File "/usr/lib/python3.10/site-packages/PIL/ImageTk.py", line 118, in __del__
    name = self.__photo.name
AttributeError: 'PhotoImage' object has no attribute '_PhotoImage__photo'

Start with tkintermapview/map_widget.py, especially pre_cache and request_image, which appear in the traceback. Reproduce closing a window while image updates run and trace the widget shutdown path. Done means the reported console exceptions no longer occur when the window closes.