diff --git a/.github/workflows/python_test.yml b/.github/workflows/python_test.yml
index 94f6b634..2ae8519a 100644
--- a/.github/workflows/python_test.yml
+++ b/.github/workflows/python_test.yml
@@ -104,7 +104,6 @@ jobs:
         # the "[tox]" subsection in "tox.ini") to be tested, which the
         # ${TOXENV} environment variable declared below exposes to "tox".
         tox-env:
-          - py39-coverage
           - py310-coverage
           - py311-coverage
           - py312-coverage
diff --git a/betse/util/py/module/pymodname.py b/betse/util/py/module/pymodname.py
index d188b3e4..4a2e860e 100644
--- a/betse/util/py/module/pymodname.py
+++ b/betse/util/py/module/pymodname.py
@@ -39,7 +39,9 @@
     initial_mapping={
         'Numpy':  'numpy',
         'Pillow': 'PIL',
+        'pillow': 'PIL',
         'PyYAML': 'yaml',
+        'pyyaml': 'yaml',
         'SciPy':  'scipy',
     }
 )