ENH: Test with Python 3.7

Author: thewtex

.github/workflows/notebook-test.yml

@@ -11,7 +11,7 @@ jobs:
 
       - uses: actions/setup-python@v3
         with:
-          python-version: '3.9'
+          python-version: '3.7'
       - uses: actions/setup-java@v3
         with:
           java-version: '8'