Time Converter - Python Tkinter - General comments on code I have been learning python since being in lockdown, this is the first Tkinter application I've built without consulting the internet or seeking help anywhere.
It is a time converter where you can select the input unit via a checkbox and the other entry windows will fill with the correct conversion.
I'd like to hear feedback on how it's written, in terms of if I have demonstrated best practice or areas where I could have used less code.
from tkinter import * 
from tkinter.ttk import*

root = Tk() 
Second = IntVar() 
Minute = IntVar() 
Hour = IntVar()

Var1 = IntVar() 
Var2 = IntVar() 
Var3 = IntVar()

def ConvertTime():
    if Var1.get() == 1:
        Minute.set(Second.get()/60)
        Hour.set(Second.get()/3600)
    
    if Var2.get() == 1:
        Second.set(Minute.get()*60)
        Hour.set(Minute.get()*0.01667)

    if Var3.get() == 1:
        Second.set(Hour.get()*3600)
        Minute.set(Hour.get()*60)

class GUI:

    def __init__(self, master):

        self.master = master
        master.title('Time Converter')
        master.geometry('+600+300')

        master.bttn = Button(root, text = 'Convert', command = ConvertTime)
        master.bttn.grid(pady= 5, padx=20, column=1, row=3)

        master.ChooseSecond = Checkbutton(root, text = 'Seconds', variable=Var1, onvalue = 1, offvalue = 0)
        master.ChooseSecond.grid(pady=5, padx=20, column=0, row=0)

        master.entry1 = Entry(root, textvariable=Second)
        master.entry1.grid(pady=5, padx=20, column=0, row=1)

        master.ChooseMinute = Checkbutton(root, text = 'Minutes', variable=Var2, onvalue = 1, offvalue=0)
        master.ChooseMinute.grid(pady=5, padx=20, column=1, row=0)

        master.entry2 = Entry(root, textvariable=Minute)
        master.entry2.grid(pady=5, padx=20, column=1, row=1)

        master.ChooseHour = Checkbutton(root, text = 'Hours',variable=Var3, onvalue=1, offvalue=0)
        master.ChooseHour.grid(pady=5, padx=20, column=2, row=0)

        master.entry3 = Entry(root, textvariable=Hour)
        master.entry3.grid(pady=5, padx=20, column=2, row = 1)

def main():
    GUI(root)
    root.mainloop()

main()
One issue I can see on first glance is the *. It's considered bad practice to import everything like that, and here is why from this Stack Overflow post:


Because it puts a lot of stuff into your namespace (might shadow some other object from previous import and you won't know about it).
Because you don't know exactly what is imported and can't easily find from which module a certain thing was imported (readability).
Because you can't use cool tools like pyflakes to statically detect errors in your code.