DeprecationWarning QDialogButtonBox StandardButton

With Python 3.8 the following warning is generated whenever I use a member from the
QDialogButtonBox.StandardButton enum, e.g. QDialogButtonBox.StandardButton.Ok:

 DeprecationWarning: an integer is required (got type PySide2.QtWidgets.QDialogButtonBox.StandardButton). Implicit conversion to integers using __int__ is deprecated, and may be removed in a future version of Python.
 buttonbox = QDialogButtonBox(QDialogButtonBox.Ok |

This warning is specific to Python 3.8 (it does not occur with earlier Python versions such as 3.7) and PySide2 (it does not occur with PyQt5 on Python 3.8).