NoneType' object has no attribute delete [duplicate]

Question

I have created a program that creates a citation based on entrybox inputs. I am trying to add a button that clears all the entryboxes when clicked; however, I find that the error 'NoneType' object has no attribute delete occurs since none of my entry boxes are packed. When I do replace .place() with .pack(), I find that it works. Is there any way to make this function work with un-padded entry boxes (as I need these boxes in specific locations)?
This is the sample of my code:

from tkinter import *

#create window
win = Tk()
win.geometry("800x500")

#clear function
def clearBoxes():
    author1Input.delete(0,END)

#entry box
author1 = StringVar()
author1Input = Entry(win,textvariable=author1).place(x=30,y=120)

#button to clear
Button(win,text="Clear",command=clearBoxes).place(x=30,y=200)

win.mainloop()