old_contents: from __future__ import print_function, division
  from sys import argv, stderr
  
  def run_gui():
      '''Start the event loop to calucate spectra interactively'''
      # Import Qt functions.  Do so here to handle errors better
      try:
          from PyQt4.QtGui import QApplication
      except ImportError:
          print("Cannot find PyQt4", file=stderr)
          print("You must install this to run the GUI", file=stderr)
          return 1
      # For good measure, try to find PyQwt5 now as a check
      try:
          import PyQt4.Qwt5
      except ImportError:
          print("Cannot find PyQwt5", file=stderr)
          print("You must install this to run the GUI", file=stderr)
          return 1
      from mainwindow import MainWindow
  
      # The actual event loop
      app = QApplication(argv)
      window = MainWindow()
      window.show()
      return app.exec_()
  
new_contents: from __future__ import print_function, division
  from sys import argv, stderr
  
  def run_gui():
      '''Start the event loop to calucate spectra interactively'''
      # Import Qt functions.  Do so here to handle errors better
      try:
          from PyQt4.QtGui import QApplication
      except ImportError:
          print("Cannot find PyQt4", file=stderr)
          print("You must install this to run the GUI", file=stderr)
          return 1
      # For good measure, try to find PyQwt5 now as a check
      try:
          import PyQt4.Qwt5
      except ImportError:
          print("Cannot find PyQwt5", file=stderr)
          print("You must install this to run the GUI", file=stderr)
          return 1
      from mainwindow import MainWindow
  
      # The actual event loop
      app = QApplication(argv)
      window = MainWindow()
      window.show()
      window.raise_()
      return app.exec_()
  
subject: Raise window to focus on Mac