How to get instance attribute value and do logic based on that? Python, Tkinter

Question

I have created a custom message box that returns True if the yes button is pressed and False if the no button is pressed. Now I want to do logic based on that in the init method of the class MainApp. How can I do this? How can I get the instance attribute value of answer from the class MessageboxYesNo? I am fairly new to OOP.

from sys import platform
import tkinter as tk


class MainApp(tk.Frame):
    
    def __init__(self, parent, *args, **kwargs):
        tk.Frame.__init__(self, parent, *args, **kwargs) 
        self.parent = parent #save root window object here when instantiating from this class

        self.set_app_size_and_position()
   
        #Exit button
        self.exitButton = tk.Button(self.parent, text="Exit", command=lambda: MessageboxYesNo(self, "QUIT", "Are you sure you want to quit?"), bg="red", fg="black")
        self.exitButton.pack(side="top", anchor='ne', padx=15, pady=10)

    #Want to do logic here based on the answer from the messagebox. How can I access the answer from the MessageboxYesNo class/instance?
    # if answer:
    #    do something

    def set_app_size_and_position(self):
        # get screen width and height
        self.screen_width = int(self.parent.winfo_screenwidth()) 
        self.screen_height = int(self.parent.winfo_screenheight())
        
        self.app_width_mac = int(self.screen_width/2)
        self.app_height_mac = int(self.screen_height)
        self.app_x_pos_mac = int(self.screen_width/2)
        self.app_y_pos_mac = 0
        
        #set the app window to half of the screens width and to the right side of the screen 
        
        if platform == "darwin":
            self.parent.geometry(f"{self.app_width_mac}x{self.app_height_mac}+{self.app_x_pos_mac}+{self.app_y_pos_mac}")



class MessageboxYesNo(tk.Frame):
    def __init__(self, parent, title, text):
        tk.Frame.__init__(self, parent)
        
        self.parent = parent #this will be root
        
        self.title = title
        self.text = text
        self.answer = None
        
        self.toplevel = tk.Toplevel(self.parent)
        
        #get the messagebox on top of the app window
        self.toplevel.focus_force()     # Get focus
        
        self.toplevel.title(self.title)
        
        #set x- and y-coordinates for centering the messagebox
        #self.parent.app_x_pos_mac will get the instance attribute value from the class MainApp
        self.x_pos_messagebox = int(self.parent.app_x_pos_mac+(self.parent.app_x_pos_mac/2))
        self.y_pos_messagebox = int(self.parent.app_height_mac/2)

        #position the messagebox near the center of the app
        self.toplevel.geometry(f"500x300+{self.x_pos_messagebox}+{self.y_pos_messagebox}") 
    
        #add labels and buttons to messagebox
        self.l1=tk.Label(self.toplevel, image="::tk::icons::question")
        self.l1.grid(row=0, column=0, pady=(7, 0), padx=(10, 30), sticky="e")

        self.l2=tk.Label(self.toplevel,text=self.text)
        self.l2.grid(row=0, column=1, columnspan=3, pady=(7, 10), sticky="w")
    
        self.b1=tk.Button(self.toplevel,text="Yes",width = 10, command=lambda: self.answerMessagebox(True))
        self.b1.grid(row=1, column=1, padx=(2, 35), sticky="e")

        self.b2=tk.Button(self.toplevel,text="No", width = 10, command=lambda: self.answerMessagebox(False))
        self.b2.grid(row=1, column=2, padx=(2, 35), sticky="e")
        
    def answerMessagebox(self, answerOnQuestion):
        
        if answerOnQuestion == True:
            print("You pressed yes")
            self.answer = True
        
        if answerOnQuestion == False:  
            print("You pressed no")
            self.answer = False 
    
        print(self.answer)
        self.toplevel.destroy() #close messagebox
        return self.answer
    

def main():
    root = tk.Tk()
    app = MainApp(root)
    app.pack()
    
    root.mainloop()
      
if __name__ == "__main__":
    main()