Detected error; Tkinter GUI using python

I am creating a simple Tkinter gui. However, it seems that something is like he is losing his mind. Nothing is really “framed” in a frame. Can anyone determine what I did wrong? (In addition to the problems caused by using "from Tkinter import" and, apparently, not useful do_nothing () function.

#/usr/bin/python
from Tkinter import *

class gui:
    def __init__(self, parent):
        f = Frame(parent, width=300, height=500)
        f.pack(padx=30, pady=15)

        self.label = Label(f, text="Japanese Trainer")
        self.label.pack(side=TOP, padx=10, pady=12)

        self.txtlbl = Entry(f, justify=CENTER, text="", font=("Calibri", 15, "bold"), width=37)
        self.txtlbl.pack()
        self.txtlbl.grid(row=1, rowspan=2, sticky=E, pady=10, padx=40)

        self.button0 = Button(f, text="Kana Trainer", width=20, command=self.do_nothing)
        self.button0.pack()
        self.button0.grid(row=3, rowspan=2, sticky=W, pady=10, padx=40)

        self.button1 = Button(f, text="Vocab Trainer", width=20, command=self.do_nothing)
        self.button1.pack()
        self.button1.grid(row=3, rowspan=2, sticky=E, pady=10, padx=40)

    def do_nothing(self):
        self.txtlbl.delete(0, END)
        self.txtlbl.insert(END, "Command did nothing...")


root = Tk()
root.title('Eg.')
app = gui(root)

root.mainloop()