title: Enable command menu in tkinter
body: <p>I have a command menu of 'Submenu' of File menu, which was initially disabled. I want to enable the command menu if a particular condition is fulfilled during execution. Please help.</p>
  
  <pre><code>menubar=tk.Menu(hW)
  filemenu=tk.Menu(menubar,tearoff=0)
  filemenu.add_command(label='Open',command=FileOpen)
  filemenu.add_command(label='Submenu',
                                  command=command1,state='disabled')
  menubar.add_cascade(label='File',menu=filemenu)
  </code></pre>