code: def test_polygon_bounding_boxes_empty():
      s = cuspatial.GeoSeries([])
      result = cuspatial.polygon_bounding_boxes(s)
      cudf.testing.assert_frame_equal(
          result,
          cudf.DataFrame(
              columns=["minx", "miny", "maxx", "maxy"], dtype="f8"
          ),
      )
  
imports: import pytest
  from shapely.geometry import MultiPolygon, Polygon
  import cudf
  import cuspatial
label_desc: Use image node_id 1 for calling a global function with example usage: test_polygon_bounding_boxes_empty() without return types