如何清除输入小部件作为输入并在按下按钮时清除输入

Question

我想将条目小部件作为输入，但即使我放入.get（）它也不起作用。我还想清除条目小部件，如果我按下“添加”按钮，当我把.clearscreen它不起作用。帮我。我是python的初学者。

def addsubject():
   global e1, e2
   frame3.place_forget()
   frame4.place_forget()

   frame5=Frame(root)
   frame5.place(relx=0.5, rely=0.3, anchor=CENTER)

   frame6=Frame(root)
   frame6.place(relx=0.5, rely=0.5, anchor=CENTER)

   label0 = Label(frame5, text="ADD SUBJECT", font=('Arial', 30, 
   'bold')).grid()

   label1 = Label(frame6, text="Enter Subject Code").grid()
   e1=Entry(frame6).grid()

   label2 = Label(frame6, text="Subject's total hour (1 sem)").grid()
   e2=Entry(frame6).grid()

   Button(frame6, text = "ADD",command=subject).grid()
   Button(frame6, text = "BACK",command=admin).grid()

def subject():
   subjectCode = e1.get()
   if subjectCode != "NO":
       totalhours = e2.get()
       file = open(subjectCode + '.txt' , 'a') 
       file.write(str(totalhours) + "\n")
       file.close()
   else:
       e1.clearscreen
       e2.clearscreen"