Tkinter exception if entries are not filled up

[balenaucigasa]

from tkinter import *
 
Appli = Tk()
Appli.title("Application de retraite")
Appli.geometry("640x640")
  
  
label1 = Label(Appli,text="Entrez votre nom: ",font=("arial",12,"bold"),bg="#2340B6", fg="white")
label1.place(x=20, y=100)
i= StringVar()
entry_box1= Entry(Appli, textvariable=i, bg="white", width="15")
entry_box1.place(x=190,y=105)
 
 
label2= Label(Appli,text="Quelle est votre année de naissance? : ",font=("arial",12,"bold"),bg="#2340B6", fg="white")
label2.place(x=20, y=175)
k= IntVar()
entry_box2= Entry(Appli, textvariable=k, bg="white", width="15")
entry_box2.place(x=340,y=180)
 
 
label3= Label(Appli,text="Quel est votre revenu mensuel sur vos six derniers mois? : ",font=("arial",12,"bold"),bg="#2340B6", fg="white")
label3.place(x=20, y=255)
revenu_moyen= IntVar()
entry_box3= Entry(Appli, textvariable=revenu_moyen, bg="white", width="15")
entry_box3.place(x=500,y=260)
 
 
label4= Label(Appli,text="Combien de trimestres avez vous cotisé? : ",font=("arial",12,"bold"),bg="#2340B6", fg="white")
label4.place(x=20, y=335)
trimestre_cotisés= IntVar()
entry_box4= Entry(Appli, textvariable=trimestre_cotisés, bg="white", width="15")
entry_box4.place(x=380,y=340)
 
 
label5= Label(Appli,text="Combien avez vous d'enfants? : ",font=("arial",12,"bold"),bg="#2340B6", fg="white")
label5.place(x=20, y=410)
enfants=IntVar()
entry_box5 = Entry(Appli, textvariable=enfants, bg="white", width="10")
entry_box5.place(x=300,y=415)

def verific():
    if not i.get() or i.get().isnumeric() == True:
        button.configure(state = DISABLED)
        Appli.after(1, verific)
    else:
        button.configure(state = NORMAL)
        Appli.after(1, verific)

def do_it():
    print("execute your function here")


button= Button(Appli, text="Calculer", width="20", height="3",command=do_it,font=("arial",12,"bold"),bg="white",fg="#2340B6")
button.place(x=20, y=500)    

verific()
Appli.mainloop()

entry_box1 is verified by this example.