old_contents: """
  Sleep without freezing the graphical user interface.
  """
  import time
  
  from .threading import Thread, Worker
  
  
  class SleepWorker(Worker):
  
      def __init__(self, seconds):
          """The :class:`~msl.qt.threading.Worker` class for :class:`Sleep`.
  
          Delays execution for a certain number of seconds without
          freezing the graphical user interface.
  
          Parameters
          ----------
          seconds : :class:`float`
              The number of seconds to sleep for. This argument is passed in from
              the :obj:`start(*args, **kwargs) <msl.qt.threading.Thread.start>`
              method of the :class:`Sleep` class.
          """
          Worker.__init__(self)
          self.seconds = seconds
  
      def process(self):
          """Calls :func:`time.sleep`."""
          time.sleep(self.seconds)
  
  
  class Sleep(Thread):
  
      def __init__(self):
          """Sleep without freezing the graphical user interface.
  
          The following example illustrates how one can use :class:`Sleep`
          and keep the GUI active:
  
          .. literalinclude:: ../../msl/examples/qt/loop_until_abort_sleep.py
  
          Example
          -------
          To run this example enter the following:
  
          >>> from msl.examples.qt import LoopExampleSleep
          >>> loop = LoopExampleSleep() # doctest: +SKIP
          >>> loop.start() # doctest: +SKIP
          """
          Thread.__init__(self, SleepWorker)
  
new_contents: """
  Sleep without freezing the graphical user interface.
  """
  import time
  
  from .threading import Thread, Worker
  
  
  class SleepWorker(Worker):
  
      def __init__(self, seconds):
          """The :class:`~msl.qt.threading.Worker` class for :class:`Sleep`.
  
          Delays execution for a certain number of seconds without
          freezing the graphical user interface.
  
          Parameters
          ----------
          seconds : :class:`float`
              The number of seconds to sleep for.
          """
          super(SleepWorker, self).__init__()
          self.seconds = seconds
  
      def process(self):
          """Calls :func:`time.sleep`."""
          time.sleep(self.seconds)
  
  
  class Sleep(Thread):
  
      def __init__(self):
          """Sleep without freezing the graphical user interface.
  
          The following example illustrates how one can use :class:`Sleep`
          and keep the GUI active:
  
          .. literalinclude:: ../../msl/examples/qt/loop_until_abort_sleep.py
  
          Example
          -------
          To run this example enter the following::
  
          >>> from msl.examples.qt import LoopExampleSleep  # doctest: +SKIP
          >>> loop = LoopExampleSleep()  # doctest: +SKIP
          >>> loop.start()  # doctest: +SKIP
          """
          super(Sleep, self).__init__(SleepWorker)
  
subject: use super() for the SleepWorker constructor and simplify the docstring