python - problems with the update of a label Tkinter -

i'm stuck on basilary things: have code

from tkinter import * import sys  import subprocess  import tkinter tk  def cd():       f=(subprocess.check_output("net view"))     e=(f.decode(sys.stdout.encoding))     label1=label(text=e).pack()   def mainscreen():      mainscreen=tk()     mainscreen.title("terfysgol's kit v 2.0")     frame1=frame(mainscreen)     frame1.pack()     puls1=button(frame1,text="list of device", borderwidth= "2",command= cd).pack()  mainscreen() 

when run time press button create new label want update text of label1.

this after:

def cd():      f=(subprocess.check_output("net view"))     e=(f.decode(sys.stdout.encoding))     label1.config(text = e) 

and @ top of program after imports need put:

label1 = label() label1.pack() 

please note i'm not suggesting program structure, sort out. answer quick fix provide enough information work out rest of need.

also can remove import tkinter tk line imports tkinter.