I’m trying to plot signals picked up from a microcontroller. I’ve had problems with port names and now I have this problem that I simply cannot find a solution to.

Here is the full error message:

Traceback (most recent call last):
  File "/opt/anaconda3/lib/python3.11/tkinter/__init__.py", line 1948, in __call__
    return self.func(*args)
           ^^^^^^^^^^^^^^^^
  File "/opt/anaconda3/lib/python3.11/tkinter/__init__.py", line 864, in callit
    self.deletecommand(name)
  File "/opt/anaconda3/lib/python3.11/tkinter/__init__.py", line 697, in deletecommand
    self._tclCommands.remove(name)
    ^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'remove'

And this is the part of the code which probably contains the problem:

if __name__ == '__main__':
    root = tk.Tk()

    # Window
    root.title('XXX')
    root.geometry('500x250')
    root.resizable(False, False)

    # Widget
    button1 = tk.Button(root, text='Start', width=6, height=4, font=('Arial', 25),
                     cursor='hand2', bg='gray', command=lambda: main(button1))
    button1.pack(padx=20, pady=0, side=tk.RIGHT)

    label1 = tk.Label(root, font=('Arial', 15), text='')
    label1.place(x=20, y=140)

    label2 = tk.Label(root, font=('Arial', 15), text='　　  COM：')
    label2.place(x=20, y=40)

    label3 = tk.Label(root, font=('Arial', 15), text='')
    label3.place(x=20, y=180)

    entry = tk.Entry(root, font=('Arial', 15), width=3)
    entry.place(x=140, y=40)
    entry.insert(tk.END, '128')

    root.mainloop()

I thought the issue was the way the ‘main’ function was being called as the command for the button.
I have tried command = main, command = main(), command=lambda: main(button1) and I still get the same problem.