I have a frame with a check button located in a main window. I need to create a pop up when the check button is clicked, but I face the following error:

open_popup() takes 0 positional arguments but 1 was given

How can I fix this error?

import pandas as pd
import numpy as np
from standard_precip import spi
import tkinter as tk
from tkinter import ttk
from tkinter import filedialog
from tkinter.messagebox import showinfo
import os
from matplotlib.backends.backend_tkagg import (FigureCanvasTkAgg, 
NavigationToolbar2Tk)
from tkinter import * 
from PIL import Image, ImageTk



class EGEDT(tk.Frame):
    def __init__(self, master=None):
        super().__init__(master)
        self.master = master
        self.pack()
        self.create_widgets()
        # dimensions of the main window
        master.geometry("300x300")

    def create_widgets(self):
        self.top_frame = ttk.Frame(self)

        padding_x = 8
        padding_y = 7
        self.working_dir = "/"
               
        # Create a check button   
        self.ab_frame = ttk.Frame(self.top_frame)
        self.ab_label = ttk.Label(self.ab_frame, text="Select the check button:")
        self.ab_label.grid(row=1, column=0, padx= 5, pady= 5)
        
        self.a = ttk.Checkbutton(self.ab_frame,text="SPI", onvalue=1, offvalue=0,command=self.open_popup)
        self.a.grid(row=2, column=1, padx= 0, pady= 0)
        self.ab_frame.grid(row=2, column=0, sticky=tk.W, padx=padding_x, pady=padding_y)       
        self.top_frame.grid(row=0, column=0)
        
    def open_popup():
       top= Toplevel(self.top_frame)
       top.geometry("750x250")
       top.title("Child Window")
       Label(top, text= "Hello World!", font=('Mistral 18 bold')).place(x=150,y=80)
        
def main():
    root = tk.Tk()   
    root.title("Main window")
    app = EGEDT(master=root)
    app.mainloop()

main()

>Solution :

You need to include the self parameter in the definition of open_popup since it’s a method of the EGEDT class, and the class is passed to the method as an implicit first argument

def open_popup(self):  # add 'self' here
    top = Toplevel(self.top_frame)
    top.geometry("750x250")
    top.title("Child Window")
    Label(top, text= "Hello World!", font=('Mistral 18 bold')).place(x=150,y=80)