Problem with askopenfilename() sending to converting function and saving file using asksavefile() - Python Tkinter - python-3.x

Question

I wrote a CAD coordinate conversion application that reads a .txt file using filedialok.askopenfilename() using the function read_file_click().
After selecting the appropriate scale in the Combobox, the program converts the file using the convert() function, then saves it to a .txt file after calling the function save_file_click().
The problem is that when I send the returned value from the convert function to the save_file_click() function, I get two notifications about opening the file.
I don't know how to correct this error. I tried using global variables, but it doesn't help, and weak errors appears with the data_list_no_head variable. Thanks for help:)
from tkinter import *
from tkinter import ttk
from tkinter import filedialog
import os
root = Tk()
root.title("Autocad Coordinate Converter")
root.geometry("")
root.geometry("280x320")
root.resizable(False, False)
def combo_sets():
scale_combo.set("")
def ending_message():
messagebox.showinfo("Autocad Coordinate Converter", "End")
def read_file_click():
global data_list_no_head
file_path = filedialog.askopenfilename()
return file_path
def convert():
file_path_new = read_file_click()
data_list = []
with open(file_path_new, encoding='utf-16') as file:
for line in file:
data_list.append(line.split())
data_list_no_head = data_list[4:]
return data_list_no_head
def save_file_click():
new = convert()
scale_get = scale_combo.get()
data = None
event_eng = None
cal = None
x_coordinate = None
y_coordinate = None
output_file = open(output_file_path_name, 'a')
if scale_get == "1:500" or scale_get == "1:1000":
for event in new:
for _ in event:
data = event[1]
event_eng = event[4]
x_coordinate = event[5]
y_coordinate = event[6]
cal = int(event_eng[-1])*2-2
output_file.write(f"_layer u w{data[2:4]}e{event_eng[-1]} _donut 0 {cal} {y_coordinate},"
f"{x_coordinate} \n")
output_file.close()
new_file_name = output_file_path_name[:-4] + ".scr.txt"
os.rename(output_file_path_name, new_file_name)
combo_sets()
ending_message()
elif scale_get == "1:2000":
for event in new:
for _ in event:
data = event[1]
event_eng = event[4]
x_coordinate = event[5]
y_coordinate = event[6]
cal = 2*(int(event_eng[-1])*2-2)
output_file.write(f"_layer u w{data[2:4]}e{event_eng[-1]} _donut 0 {cal} {y_coordinate},"
f"{x_coordinate} \n")
output_file.close()
new_file_name = output_file_path_name[:-4] + ".scr.txt"
os.rename(output_file_path_name, new_file_name)
combo_sets()
ending_message()
elif scale_get == "1:5000":
for event in new:
for _ in event:
data = event[1]
event_eng = event[4]
x_coordinate = event[5]
y_coordinate = event[6]
cal = 5*(int(event_eng[-1])*2-2)
output_file.write(f"_layer u w{data[2:4]}e{event_eng[-1]} _donut 0 {cal} {y_coordinate},"
f"{x_coordinate} \n")
output_file.close()
new_file_name = output_file_path_name[:-4] + ".scr.txt"
os.rename(output_file_path_name, new_file_name)
combo_sets()
ending_message()
elif scale_get == "1:10000":
for event in new:
for _ in event:
data = event[1]
event_eng = event[4]
x_coordinate = event[5]
y_coordinate = event[6]
cal = 20*(int(event_eng[-1])-2)
output_file.write(f"_layer u w{data[2:4]}e{event_eng[-1]} _donut 0 {cal} {y_coordinate},"
f"{x_coordinate} \n")
output_file.close()
new_file_name = output_file_path_name[:-4] + ".scr.txt"
os.rename(output_file_path_name, new_file_name)
combo_sets()
ending_message()
# Frame1
frame1 = LabelFrame(root, padx=15, pady=15, relief=FLAT)
frame1.grid(row=1, column=0)
button_1 = Button(frame1, text="Read .txt file", padx=15, pady=15, width=20, height=1, command=read_file_click)
button_1.grid(row=1, column=0, padx=3, pady=3)
# Frame2
frame2 = LabelFrame(root, padx=15, pady=15, relief=FLAT)
frame2.grid(row=2, column=0)
Label(frame2, text="Select scale:", width=14).grid(row=1, column=1, padx=1, pady=1)
scale_combo = ttk.Combobox(frame2, values=["1:500", "1:1000", "1:2000", "1:5000", "1:10000"], width=9, state='readonly')
scale_combo.current()
scale_combo.grid(row=2, column=1, padx=1, pady=1)
# Frame3
frame3 = LabelFrame(root, padx=50, pady=50, relief=FLAT)
frame3.grid(row=3, column=0)
button_2 = Button(frame3, text="Save file in CAD format", padx=15, pady=15, width=20, height=1,
command=save_file_click)
button_2.grid(row=0, column=0, padx=3, pady=3)
root.mainloop()