code: def start_event_loop_qt4(app=None):
      """Start the qt event loop in a consistent manner."""
      if app is None:
          app = get_app_qt4([""])
      if not is_event_loop_running_qt4(app):
          app._in_event_loop = True
          app.exec_()
          app._in_event_loop = False
      else:
          app._in_event_loop = True
  
imports: from IPython.core.getipython import get_ipython
label_desc: Use image node_id 6 for calling a global function with example usage: start_event_loop_qt4(app) without return types