Error when running tkinter in python " no display name and no $DISPLAY environment variable" while running the code

The error message is:

Traceback (most recent call last):  File "<stdin>", line 1, in <module>  File "/usr/lib/python3.8/tkinter/__init__.py", line 2261, in __init__    self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)_tkinter.TclError: no display name and no $DISPLAY environment variable