Get a customization object representing the customization of the activity.

        .. versionadded:: 1.11

        :return: An instance of :class:`customization.ExtCustomization`

        Example
        -------
        >>> activity = project.activity(name='Customizable activity')
        >>> customization = activity.customization()
        >>> part_to_show = project.part(name='Bike')
        >>> customization.add_property_grid_widget(part_to_show, custom_title="My super bike"))

def customization(self):
        """
        Get a customization object representing the customization of the activity.

        .. versionadded:: 1.11

        :return: An instance of :class:`customization.ExtCustomization`

        Example
        -------
        >>> activity = project.activity(name='Customizable activity')
        >>> customization = activity.customization()
        >>> part_to_show = project.part(name='Bike')
        >>> customization.add_property_grid_widget(part_to_show, custom_title="My super bike"))

        """
        from .customization import ExtCustomization

        # For now, we only allow customization in an Ext JS context
        return ExtCustomization(activity=self, client=self._client)