# importing all files from tkinter
from tkinter import *
from tkinter import ttk
# import only asksaveasfile from filedialog
# which is used to save file in any extension
from tkinter.filedialog import asksaveasfile
root = Tk()
root.geometry('200x150')
# function to call when user press
# the save button, a filedialog will
# open and ask to save file
def save():
files = [('All Files', '*.*'),
('Python Files', '*.py'),
('Text Document', '*.txt')]
file = asksaveasfile(filetypes = files, defaultextension = files)
btn = ttk.Button(root, text = 'Save', command = lambda : save())
btn.pack(side = TOP, pady = 20)
mainloop()