Подскажите плз, как сделать в этом коде увилечение шрифта с каждым нажатием кнопки?

from tkinter import *
from tkinter.filedialog import *



def plus():
    Text_vvod['font']=

def font():
    window2=Tk()
    window2.title('Font')
    But_font_pl=Button(window2, text='+', command=plus).grid(row=1, column=0)




def black():
    Text_vvod['bg']='black'
    Text_vvod['fg']='white'

def yellow():
    Text_vvod['bg']='yellow'

def cyan():
    Text_vvod['bg']='cyan'
    Text_vvod['fg']='black'

def white():
    Text_vvod['bg']='white'    


def save():
    txt=open('редактор.txt', 'w')
    txt.write(Text_vvod.get(1.0,END))
    txt.close()

window = Tk()
window.title("Редактор")
#window.geometry("300x250")

main_menu = Menu()
file_menu = Menu(tearoff=0)
edit_menu=Menu(tearoff=0)
conf_menu=Menu(tearoff=0)


main_menu.add_cascade(label="File",menu=file_menu )
main_menu.add_cascade(label="Option",menu=edit_menu )


file_menu.add_command(label="Save", command = save)
file_menu.add_command(label="Exit", command =window.destroy)


edit_menu.add_cascade(label='Configure',menu=conf_menu)
edit_menu.add_command(label='font', command=font)


conf_menu.add_command(label='black', command=black)
conf_menu.add_command(label='white', command=white)
conf_menu.add_command(label='cyan', command=cyan)
conf_menu.add_command(label='yellow', command=yellow)


window.config(menu=main_menu)
Text_vvod=Text(window,font='Arial 10')
Text_vvod.pack()
window.mainloop()