Add ISL in Python (#9437)

The pdf first published on July 5, 2023.

books/free-programming-books-langs.md

@@ -1925,6 +1925,7 @@ Books on general-purpose programming that don't focus on a specific language are
 * [A Guide to Python's Magic Methods](https://github.com/RafeKettler/magicmethods) - Rafe Kettler
 * [A Practical Introduction to Python Programming](https://www.brianheinold.net/python/) - Brian Heinold (HTML, PDF, Exercises sources)
 * [A Whirlwind Tour of Python](http://www.oreilly.com/programming/free/files/a-whirlwind-tour-of-python.pdf) - Jake VanderPlas (PDF) [(EPUB, MOBI)](http://www.oreilly.com/programming/free/a-whirlwind-tour-of-python.csp?download=yes)
+* [An Introduction to Statistical Learning with Applications in Python](https://hastie.su.domains/ISLP/ISLP_website.pdf) - Gareth James, Daniela Witten, Trevor Hastie, Robert Tibshirani, Jonathan Taylor (PDF)
 * [Architecture Patterns with Python](https://www.cosmicpython.com/book/preface.html) - Harry J.W. Percival, Bob Gregory (HTML)
 * [Automate the Boring Stuff with Python, 2nd Edition: Practical Programming for Total Beginners](https://automatetheboringstuff.com/2e/chapter0/) - Al Sweigart (3.8)
     * [Automate the Boring Stuff with Python: Practical Programming for Total Beginners](https://automatetheboringstuff.com/chapter0/) - Al Sweigart (3.4)