Create and return a new notes slide part based on the notes master
        and related to both the notes master part and *slide_part*. If no
        notes master is present, create one based on the default template.

def new(cls, package, slide_part):
        """
        Create and return a new notes slide part based on the notes master
        and related to both the notes master part and *slide_part*. If no
        notes master is present, create one based on the default template.
        """
        notes_master_part = package.presentation_part.notes_master_part
        notes_slide_part = cls._add_notes_slide_part(
            package, slide_part, notes_master_part
        )
        notes_slide = notes_slide_part.notes_slide
        notes_slide.clone_master_placeholders(notes_master_part.notes_master)
        return notes_slide_part