Backport PR matplotlib#31931: TST: address pikepdf deprecation (matplotlib#31941)

Co-authored-by: Elliott Sales de Andrade <quantum.analyst@gmail.com>

Author: meeseeksmachine

lib/matplotlib/tests/test_backend_pdf.py

@@ -5,6 +5,7 @@
 import string
 
 import numpy as np
+from packaging.version import parse as parse_version
 import pytest
 
 import matplotlib as mpl
@@ -112,7 +113,10 @@ def test_indexed_image():
 
     with pikepdf.Pdf.open(buf) as pdf:
         page, = pdf.pages
-        image, = page.images.values()
+        if parse_version(pikepdf.__version__) < parse_version('10.9.0'):
+            image, = page.images.values()
+        else:
+            image, = page.get_images().values()
         pdf_image = pikepdf.PdfImage(image)
         assert pdf_image.indexed
         pil_image = pdf_image.as_pil_image()