Simple text editor made using Tkinter

textEditor.py

from tkinter import *
from tkinter import ttk
from tkinter.filedialog import askopenfile, asksaveasfilename

class Text_Editor(object):
    def __init__(self, master):
        frame = Frame(master)
        frame.pack()
        menubar = Menu(tk)
        filemenu = Menu(menubar, tearoff=0)
        tk.config(menu=menubar)
        menubar.add_cascade(label="File", menu=filemenu)
        filemenu.add_command(label="Open", command = self.open_file)
        filemenu.add_command(label="Save", command = self.save_file)
        filemenu.add_command(label="Exit", command= tk.destroy)
        self.textfield = Text(tk, font=10)
        self.textfield.pack()
    
    def open_file(self):
        self.textfield.delete("1.0", END)
        file = askopenfile(mode="r", filetypes=[("text files", "*.txt"), ("all files", "*.*")])
        if file is not None:
            text = file.read()
            self.textfield.insert("1.0", text)
    
    def save_file(self):
        text = self.textfield.get("1.0", "end-1c")
        file = asksaveasfilename(title="Save", filetypes=[("text files", "*.txt"), ("all files", "*.*")])
        with open(file, "w") as data:
            data.write(text)


if __name__ == "__main__":
    tk = Tk()
    tk.title("Text Editor")
    Text_Editor(tk)
    tk.mainloop()