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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _on_sphinx_thread_error_msg(self, error_msg):

 """ Display error message on Sphinx rich text failure"""

        self._sphinx_thread.wait()
        self.plain_text_action.setChecked(True)
        sphinx_ver = programs.get_module_version('sphinx')
        QMessageBox.critical(self,
                    _('Help'),
                    _("The following error occured when calling "
                      "<b>Sphinx %s</b>. <br>Incompatible Sphinx "
                      "version or doc string decoding failed."
                      "<br><br>Error message:<br>%s"
                      ) % (sphinx_ver, error_msg))