Return the new `p:pic` element referencing the video.

def _pic(self):
        """Return the new `p:pic` element referencing the video."""
        return CT_Picture.new_video_pic(
            self._shape_id, self._shape_name, self._video_rId,
            self._media_rId, self._poster_frame_rId, self._x, self._y,
            self._cx, self._cy
        )