code: def comittoapi(api):
      
      global USED_API
      assert USED_API is None, "committoapi called again!"
      check = ["PyQt4", "PyQt5", "PySide", "PySide2"]
      assert api in [QT_API_PYQT5, QT_API_PYQT4, QT_API_PYSIDE, QT_API_PYSIDE2]
      for name in check:
          if name.lower() != api and name in sys.modules:
              raise RuntimeError(
                  "{} was already imported. Cannot commit to {}!"
                  .format(name, api)
              )
      else:
          api = _intern(api)
          USED_API = api
          AnyQt.__SELECTED_API = api
          AnyQt.USED_API = api
docs: Commit to the use of specified Qt api.
  
      Raise an error if another Qt api is already loaded in sys.modules