def load_student(self, event=None):
    lb_widget = event.widget
    index = str(lb_widget.curselection()[0] + 1)  #????
    self.curr_student = index

    try:
        result = self.theCursor.execute("SELECT ID, FName, LName, Telefon, Wiek, PName FROM Students WHERE ID=" + index)

        for row in result:

            stud_id = row[0]
            stud_fname = row[1]
            stud_lname = row[2]
            stud_telefon = row[3]
            stud_wiek = row[4]
            stud_pname = row[5]

            self.imie_value.set(stud_fname)
            self.nazwisko_value.set(stud_lname)
            self.telefon_value.set(stud_telefon)
            self.wiek_value.set(stud_wiek)
            self.imierodzica_value.set(stud_pname)

    except sqlite3.OperationalError:
        print("The Table Doesn't Exist")

    except:
        print("2 : Couldn't Retrieve Data From Database")


def delete_student(self):

    try:
        self.db_conn.execute("DELETE FROM Students WHERE ID=" + self.curr_student)
        self.db_conn.commit()

    except sqlite3.OperationalError:
        print("Data couldn't be Deleted")

    self.imie.delete(0, "end")
    self.nazwisko.delete(0, "end")
    self.telefon.delete(0, "end")
    self.wiek.delete(0, "end")
    self.imierodzica.delete(0, "end")

    self.update_listbox()

def update_listbox(self):

    self.list_box.delete(0, END)

    try:
        result = self.theCursor.execute("SELECT ID, FName, LName, Telefon, Wiek, PName FROM Students")

        for row in result:
            stud_id = row[0]
            stud_fname = row[1]
            stud_lname = row[2]
            stud_telefon = row[3]
            stud_wiek = row[4]
            stud_pname = row[5]

            self.list_box.insert(stud_id,
                            stud_fname + " " +
                            stud_lname + " " +
                            stud_telefon + " " +
                            stud_wiek + " " +
                            stud_pname)

    except sqlite3.OperationalError:
        print("The Table Doesn't Exist")

    except:
        print("1: Couldn't Retrieve Data From Database")