How to use the harvesters._private.frontend.pyqt5.about.About function in harvesters

content += 'Copyright (c) 2018 Brian Warner\n'
        content += 'https://github.com/warner/python-versioneer'

        self._text = QPlainTextEdit(content)
        self._text.setReadOnly(True)
        self._text.setFont(get_system_font())
        self._text.setLineWrapMode(True)
        self._text.setFixedWidth(480)

        layout.addWidget(self._text)
        self.setLayout(layout)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    about = About()
    about.show()
    sys.exit(app.exec_())

#
        button_dev_attribute = ActionShowAttributeController(
            icon='device_attribute.png', title='Device Attribute', parent=self,
            action=self.action_on_show_attribute_controller,
            is_enabled=self.is_enabled_on_show_attribute_controller
        )
        shortcut_key = 'Ctrl+a'
        button_dev_attribute.setToolTip(
            compose_tooltip('Edit device attribute', shortcut_key)
        )
        button_dev_attribute.setShortcut(shortcut_key)
        button_dev_attribute.toggle()
        observers.append(button_dev_attribute)

        #
        self._widget_about = About(self)
        button_about = ActionShowAbout(
            icon='about.png', title='About', parent=self,
            action=self.action_on_show_about
        )
        button_about.setToolTip(
            compose_tooltip('Show information about Harvester')
        )
        button_about.toggle()
        observers.append(button_about)

        #
        self._widget_device_list = ComboBox(self)
        self._widget_device_list.setSizeAdjustPolicy(
            QComboBox.AdjustToContents
        )
        shortcut_key = 'Ctrl+Shift+d'

#
        button_dev_attribute = ActionShowAttributeController(
            icon='device_attribute.png', title='Device Attribute', parent=self,
            action=self.action_on_show_attribute_controller,
            is_enabled=self.is_enabled_on_show_attribute_controller
        )
        shortcut_key = 'Ctrl+a'
        button_dev_attribute.setToolTip(
            compose_tooltip('Edit device attribute', shortcut_key)
        )
        button_dev_attribute.setShortcut(shortcut_key)
        button_dev_attribute.toggle()
        observers.append(button_dev_attribute)

        #
        self._widget_about = About(self)
        button_about = ActionShowAbout(
            icon='about.png', title='About', parent=self,
            action=self.action_on_show_about
        )
        button_about.setToolTip(
            compose_tooltip('Show information about Harvester')
        )
        button_about.toggle()
        observers.append(button_about)

        #
        self._widget_device_list = ComboBox(self)
        self._widget_device_list.setSizeAdjustPolicy(
            QComboBox.AdjustToContents
        )
        shortcut_key = 'Ctrl+Shift+d'