code: def qapp():
      app = mkQApp()
      if app is None:
          app = mkQApp()
      yield app
      app.processEvents(
          QtCore.QEventLoop.ProcessEventsFlag.AllEvents, 100
      )
  
file_path: pyqtgraph/tests/test_signalproxy.py
imports: import pytest
  from pyqtgraph import SignalProxy
  from pyqtgraph.Qt import QtCore, mkQApp
label_desc: Use image node_id 1 for calling a global function with example usage: qapp() without return types