Transforms bounding box into a polygon object in the area CRS.

        :param bbox: A bounding box
        :type bbox: BBox
        :return: A polygon
        :rtype: shapely.geometry.polygon.Polygon

def _bbox_to_area_polygon(self, bbox):
        """Transforms bounding box into a polygon object in the area CRS.

        :param bbox: A bounding box
        :type bbox: BBox
        :return: A polygon
        :rtype: shapely.geometry.polygon.Polygon
        """
        projected_bbox = bbox.transform(self.crs)
        return projected_bbox.geometry