title: Python tkinter grid_forget()
body: <p>I want to make a label appear and disappear, but I am having a problem with <code>grid_forget()</code>.  This is part of the code:</p>
  
  <pre><code>def creabackuno():
      showinfo( "Wait..","I am creating the backup, please wait...")
      vsl=Label(gui,text="Working, please wait...",font=("arial",16)).grid(row=20,rowspan=1,column=0,columnspan=1,padx=10,sticky=N)
      try:
          copytree(path,r"backup\dirbackup1\.minecraft")
          showinfo( "OK!","Backup (1) created!")
          vsl.grid_forget()
      except OSError:
          showerror( "Nope!","There is already a backup to restore")
          vsl.grid_forget()
  </code></pre>
  
  <p>And this is the error of the console:</p>
  
  <pre><code>AttributeError: 'NoneType' object has no attribute 'grid_forget'
  </code></pre>