From what I deduced, you're trying to delete the content from the entry widget.
tkinter.Entry.delete('0',END)
This should do it.
Let's imagine, I have a simple tkinter program: only tkinter.Entry(), where I can write down some text. The main goal I have set to this tkinter.Entry() is to make next: when I try to input there some symbol, it is immediately deleted from tkinter.Entry(). So the question is how to make tkinter.Entry() delete every symbol, when it have been just input there?
I hope the problem is fully described. Thanks in advance for your help.

I apologize, but it seems to me that this question has lost its former relevance for me. Sorry for letting you take all of your precious time. I took all the answers and tips into account. I will delete the question soon. Thank you for your attention to me
How to immediately delete just input symbol in tkinter.Entry()