docs(python): Minor tweak in code example in section Expressions/Aggr…

…egation (pola-rs#12033)

Co-authored-by: Stijn de Gooijer <[email protected]>

docs/src/python/user-guide/expressions/aggregation.py

@@ -158,7 +158,9 @@ def get_person() -> pl.Expr:
         get_person().first().alias("youngest"),
         get_person().last().alias("oldest"),
         get_person().sort().first().alias("alphabetical_first"),
-        pl.col("gender").sort_by("first_name").first().alias("gender"),
+        pl.col("gender")
+        .sort_by(pl.col("first_name").cat.set_ordering("lexical"))
+        .first(),
     )
     .sort("state")
     .limit(5)