title: Execute code in form load pyside and python
body: <p>when I add code to be executed in <strong>init</strong> method of the form it executes before form shown, and I want to execute my code after form displayed to user
  I tried to override show() and showEvent() methods but still same behavior </p>
  
  <p>from PySide.QtGui import *
  from PySide.QtCore import *
  from Ui_frmGreeting import Ui_frmGreeting</p>
  
  <pre><code>class frmGreeting(QDialog, Ui_frmGreeting):
      def __init__(self):
          QDialog.__init__(self)
          self.setupUi(self)
          QMessageBox.information(self, 'Registeration done', 'You have registered successfully')
  </code></pre>
  
  <p>the message appears before form displayed and I want to show it after form displayed</p>