import sqlite3
import re
from tkinter import messagebox

onlyNumber = r'^d+$'
onlyLetters = r'^[a-zA-Zs]+$'
onlyAge = r'^d+$'


def insertStudent(student_id, full_name, age):
    if re.match(onlyNumber, student_id) and re.match(onlyLetters, full_name) and re.match(onlyAge, age):
        try:
            with sqlite3.connect('school.sqlite') as conn:
                cursor = conn.cursor()
                cursor.execute("INSERT INTO student (StudentID, FullName, Age) VALUES (?, ?, ?)",
                               (student_id, full_name, age))
                conn.commit()
                messagebox.showinfo("Success", "Student successfully added to the database.")
        except sqlite3.Error as e:
            print(f"An error occurred: {e}")
            messagebox.showerror("Error", "An error occurred while adding the student to the database.")
    else:
        print("Invalid input. Only numbers allowed for ID and Age, and only letters for Full Name.")
        messagebox.showerror("Invalid Input", "Please enter valid data.")





from tkinter import *
import customtkinter as ctk
from school.backendSchool import insertStudent


windowMenu = ctk.CTk()
studentEntry = ctk.CTk()
windowMenu.title("Menu")
windowMenu.geometry("1280x720")


def buttonToMenu():
    studentEntry.withdraw()
    windowMenu.deiconify()


def buttonToStudent():
    windowMenu.withdraw()
    studentEntry.title("Student Entry")
    studentEntry.geometry("1280x720")
    studentEntry.deiconify()


entryStudentID = ctk.CTkEntry(studentEntry)
entryStudentID.pack(anchor=CENTER)

entryStudentName = ctk.CTkEntry(studentEntry)
entryStudentName.pack(anchor=CENTER)

entryStudentAge = ctk.CTkEntry(studentEntry)
entryStudentAge.pack(anchor=CENTER)

buttonStudentTable = ctk.CTkButton(studentEntry, text="Create Student",
                                   command=lambda: insertStudent(entryStudentID.get().strip(),
                                                                 entryStudentName.get().strip(),
                                                                 entryStudentAge.get().strip()))
buttonStudentTable.pack(anchor=CENTER)

buttonStudent = ctk.CTkButton(windowMenu, text="Student", command=buttonToStudent)
buttonStudent.pack(anchor=CENTER)

buttonMenu = ctk.CTkButton(studentEntry, text="Menu", command=buttonToMenu)
buttonMenu.pack(anchor=CENTER)

buttonToQuit = ctk.CTkButton(windowMenu, text="Quit", command=windowMenu.destroy)
buttonToQuit.pack(anchor=CENTER)

buttonToQuitStudent = ctk.CTkButton(studentEntry, text="Quit", command=studentEntry.destroy)
buttonToQuitStudent.pack(anchor=CENTER)

windowMenu.mainloop()

I have the problem that after typing some information into the entries and clicking on the insert data button i get the exception all the time, i was not able to find the cause of this exception.

I tried everything and even using AI!
Please help.
I added the picture for potential project structure questions