Temperature converter in ttk

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# pip install ttkbootstrap (Instale essa belezinha)

import ttkbootstrap as ttk
from ttkbootstrap.constants import *

root = ttk.Window(themename="journal")

def calcular():
    F = float(textbox_one.get())
    C = (F-32) * 5/9
    valor_final.set(str(round(C, 1)) + 'ºC Graus Celsius')


valor_final = ttk.StringVar()

label_one = ttk.Label(root, text='Graus Fahrenheit:',
                      bootstyle='info')
label_one.place(x=100, y=10)

textbox_one = ttk.Entry(root)
textbox_one.place(x=100, y=35)

button_one = ttk.Button(root, text='Calcular',command=lambda:calcular(),
                      bootstyle=(INFO, OUTLINE))
button_one.place(x=100, y=75)

label_two = ttk.Label(root, textvariable=valor_final, bootstyle='info')
label_two.place(x=100, y=120)

root.title('App - Conversor de Temperatura')
root.resizable(False, False)
root.eval('tk::PlaceWindow . center')
root.geometry('350x150')
root.mainloop()