Error: name 'self' is not defined

Question

I’m a beginner in Python and I’m developing my first program. It’s like this:

from tkinter import *
from tkinter import font

class Application(Frame):
 def __init__(self, master=None):
 pass
 self.msg = Label(self, text="Bem vindos a GUIDA!!", fg = 'blue', font = 'Candara')
self.msg.place(x=50,y=70)
self.bye = Button (self, text="Bye", command=self.quit)
self.bye.pack ()
self.pack()
self.msg_2 = Label(self, text="Selecione os tópicos e exclareça suas dúvidas!", fg = 'black', font = 'Candara')
self.msg_2.place(x=80,y=100)
self.view = Button (self, text="Ver Tópicos", font = "Algerian", command = comando, fg = 'black', bg = 'white', activebackground = 'white', activeforeground = 'yellow')
self.view.place(x=400,y=100)

root = Tk()

root["bg"] = "green"

root.title('GUIDA')

root.geometry('750x700')

app = Application()

mainloop()

But when I run, it opens like this:

I wanted to know how to solve this mistake.