old_contents: # -*- coding: utf-8 -*-
  
  import logging
  
  from PyQt4 import QtCore, QtGui
  
  from .engine import StorjEngine
  from .login import LoginUI
  from .qt_interfaces.initial_window_ui_new import Ui_InitialWindow
  from .registration import RegisterUI
  
  
  class InitialWindowUI(QtGui.QMainWindow):
      """Initial window section."""
  
      __logger = logging.getLogger('%s.InitialWindowUI' % __name__)
  
      def __init__(self, parent=None):
          QtGui.QWidget.__init__(self, parent)
          self.ui_initial_window = Ui_InitialWindow()
          self.ui_initial_window.setupUi(self)
  
          # open bucket manager
          # QtCore.QObject.connect(
          #   self.ui.pushButton_3,
          #   QtCore.SIGNAL("clicked()"),
          #   self.save_config)
  
          self.storj_engine = StorjEngine()
  
          # open login window
          QtCore.QObject.connect(
              self.ui_initial_window.login_bt,
              QtCore.SIGNAL('clicked()'),
              self.open_login_window)
  
          # open registration window
          QtCore.QObject.connect(
              self.ui_initial_window.register_bt,
              QtCore.SIGNAL('clicked()'),
              self.open_register_window)
  
          # open about window
          # QtCore.QObject.connect(
          #   self.ui_initial_window.about_bt,
          #   QtCore.SIGNAL("clicked()"),
          #   self.open_about_window)
  
      def open_login_window(self):
          self.login_window = LoginUI(self)
          self.login_window.show()
          # initial_window.hide()
  
      def open_register_window(self):
          self.register_window = RegisterUI(self)
          self.register_window.show()
  
new_contents: # -*- coding: utf-8 -*-
  
  import logging
  
  from PyQt4 import QtCore, QtGui
  
  from .engine import StorjEngine
  from .login import LoginUI
  from .qt_interfaces.initial_window_ui_new import Ui_InitialWindow
  from .registration import RegisterUI
  
  
  class InitialWindowUI(QtGui.QMainWindow):
      """Initial window section."""
  
      __logger = logging.getLogger('%s.InitialWindowUI' % __name__)
  
      def __init__(self, parent=None):
          QtGui.QWidget.__init__(self, parent)
          self.ui_initial_window = Ui_InitialWindow()
          self.ui_initial_window.setupUi(self)
  
          self.storj_engine = StorjEngine()
  
          # Open login window
          QtCore.QObject.connect(
              self.ui_initial_window.login_bt,
              QtCore.SIGNAL('clicked()'),
              self.open_login_window)
  
          # Open registration window
          QtCore.QObject.connect(
              self.ui_initial_window.register_bt,
              QtCore.SIGNAL('clicked()'),
              self.open_register_window)
  
      def open_login_window(self):
          self.login_window = LoginUI(self)
          self.login_window.show()
          # initial_window.hide()
  
      def open_register_window(self):
          self.register_window = RegisterUI(self)
          self.register_window.show()
  
subject: remove commented code