title: Restricting the value in Tkinter Entry widget
body: <p>I need to restrict the values in the Entry widget to numbers only. The way I implemented is:</p>
  
  <pre><code>import numpy as np
  from Tkinter import *;
  import tkMessageBox;
  
  class window2:
  
      def __init__(self,master1):
  
          self.panel2=Frame(master1)
          self.panel2.grid()
  
          self.button2=Button(self.panel2,text="Quit",command=self.panel2.quit)
          self.button2.grid()
  
          self.text1=Entry(self.panel2)
          self.text1.grid()
          self.text1.bind('&lt;KeyPress&gt;', self.keybind1)
          self.text1.focus()
  
      def keybind1 (self,event):
          if event.int in np.linspace(0,9,10):
              print event.int
  
  
  root1=Tk()
  window2(root1)
  root1.mainloop()
  </code></pre>
  
  <p>I keep getting error message that Event instance has no attribute 'int'. What should I do? </p>