docstr: DEPRECATED since IPython 5.0
  
  Enable event loop integration with PyQt4.
  
  Parameters
  ----------
  app : Qt Application, optional.
      Running application to use.  If not given, we probe Qt for an
      existing application object, and create a new one if none is found.
  
  Notes
  -----
  This methods sets the PyOS_InputHook for PyQt4, which allows
  the PyQt4 to integrate with terminal based applications like
  IPython.
  
  If ``app`` is not given we probe for an existing one, and return it if
  found.  If no existing app is found, we create an :class:`QApplication`
  as follows::
  
      from PyQt4 import QtCore
      app = QtGui.QApplication(sys.argv)
code: def enable(self, app=None):
      """DEPRECATED since IPython 5.0
  
      Enable event loop integration with PyQt4.
  
      Parameters
      ----------
      app : Qt Application, optional.
          Running application to use.  If not given, we probe Qt for an
          existing application object, and create a new one if none is found.
  
      Notes
      -----
      This methods sets the PyOS_InputHook for PyQt4, which allows
      the PyQt4 to integrate with terminal based applications like
      IPython.
  
      If ``app`` is not given we probe for an existing one, and return it if
      found.  If no existing app is found, we create an :class:`QApplication`
      as follows::
  
          from PyQt4 import QtCore
          app = QtGui.QApplication(sys.argv)
      """
      warn(
          "This function is deprecated since IPython 5.0 and will be removed in future versions.",
          DeprecationWarning,
          stacklevel=2,
      )
      from IPython.lib.inputhookqt4 import create_inputhook_qt4
  
      app, inputhook_qt4 = create_inputhook_qt4(self.manager, app)
      self.manager.set_inputhook(inputhook_qt4)
      if _use_appnope():
          from appnope import nope
  
          nope()
  
      return app
  
imports: import os
  import platform
  import sys
  from distutils.version import LooseVersion
  from warnings import warn
label_desc: Use image node_id 1 for calling the Qt4InputHook obj's underlying member method code with example usage: obj.enable(app) and returns: app