title: restart error with no output
body: <p>I'm new to coding, I'm trying to replicate a code for a simple calculator, when I try to run the module is gives me a restart error and nothing happens </p>
  
  <p>code is </p>
  
  <pre><code>from tkinter import*
  
  def frame(root, side):
      w=Frame(root)
      w.pack(side=side, expand=YES, fill=BOTH)
      return w
  
  def button(root,side,text, command=None):
      w=Button(root,text=text, command=command)
      w.pack(side=side, expand=YES,fill=BOTH)
      return w
  
  class Calculator(Frame):
      def __init__ (self):
          Frame.__init__(self)
          self.pack(expand=YES, fill=BOTH)
          self.master.tittle('simple Calculator')
          self.master.iconname('calcl')
  
          display = StringVar()
          Entry(self, relief=SUNKEN,
                textvariable=display).pack(side=TOP, expand=YES, fill=BOTH)
          for key in ('123', '456', '789' '-0'):
              keyF= frame(self, TOP)
              for char in ket:
                  button (keyF, LEFT, char, lambda w=display, s='%s '%char:w.set(w.get()+s))
              opsF= frame(self, TOP)
              for char in '+-/*=':
                  if char=='=':
                      btn=button(opsF, LEFT, char)
                      btn.bind('&lt;ButtonRelease-1&gt;',lambda e, s=self, w=display: s.calc(w), '+')
                  else:
                      btn=button (opsF, LEFT, char, lambda w=display, c=chair: w.set(w.get()+' '+c+' '))
              clearF = frame (self, BOTTOM)
              button(clearF, LEFT, 'CLr', lambda w=display: w.set(''))
  
      def calc(self, display):
          try:
               display.set('eval(display.get())')
          except ValueError:
                   display.set('ERROR')
  
  if __name__ == 'main__':
      Calculator().mainloop()
  </code></pre>
  
  <p>error :</p>
  
  <blockquote>
    <p>= RESTART: C:\Users\sibiyass\AppData\Local\Programs\Python\Python36\calc1.py =</p>
  </blockquote>