How can I use the variable (local) that is inside a class outside the class (global)?

I am new to the world of programming. You can help me understand how I can use an instance variable globally. In this case I would like to use the variables self.x and self.y outside the class. Thanks !!!

    import tkinter as tk
    import win32gui
    from PIL import ImageGrab

    class TestApp:
        def __init__(self, master):
            frame = tk.Frame(master)
            frame.pack()

            self.master = master

            b1 = tk.Button(text='ok', command=self.pressed)
            b1.pack()

        def pressed(self):
            self.x = ventana.winfo_x()+7
            self.y = ventana.winfo_y()+30
            print('tkinter location: ({},{})'.format(self.x, self.y))

    ventana = tk.Tk()
    ventana.title("Palynology")
    ventana.geometry('300x300')
    ventana.configure(background='blue')
    ventana.attributes('-alpha', 0.5)
    app = TestApp(ventana)
    ventana.mainloop()

    #img = ImageGrab.grab(bbox=(x,y,x+300,y+300)) #x1, y1, x2, y2
    #img.show()