title: How to set focus in tkinter entry box
body: <p>have spent a while looking for an answer. I'm new to Python but not to coding in general. Finding the various versions quite challenging!</p>
  
  <p>Anyway I'm very Gui orientated and have managed to get tkinter working with Python 3.5.1</p>
  
  <p>Just playing with basics and have the following code but cannot set focus to the first entry box. Have tried mEntry1.focus() and mEntry1.focus_set() but always get object has no attribute error. Any help?</p>
  
  <pre><code>from tkinter import *
  
  def calc(*args):
    try:
        value1 = float(V1.get())
        value2 = float(V2.get())
        result.set(value1 * value2)
    except ValueError:
      pass
  mGui = Tk()
  mGui.geometry('450x450+200+200')
  mGui.title('Test Gui')
  V1 = StringVar()
  V2 = StringVar()
  result = StringVar()
  mEntry1 = Entry(textvariable=V1,width=10).grid(row=0,column=0,sticky=W)
  mEntry2 = Entry(textvariable=V2).grid(row=1,column=0)
  mButton = Button(text='Calculate',command=calc).grid(row=3,column=0)
  mlabel = Label(textvariable=result).grid(row=4,column=2)
  </code></pre>