[Tkinter] Entry widget : unable to get the text entered

[metulburr]

Its textvariable, not textstring

import tkinter as tk
root = tk.Tk()
root.geometry('600x400+80+40')

class App:
    def __init__(self, root):
        self.entry_var = tk.StringVar()
        self.entry = tk.Entry(root, textvariable=self.entry_var)
        self.entry.bind('<Return>', self.show_output)
        self.entry.pack()
        
    def show_output(self, event):
        print(self.entry_var.get())
        
App(root)
tk.mainloop()