changed days_of_week to raise ValueError and updated docstring

Author: sharkipelago

doc/source/whatsnew/v3.0.0.rst

@@ -77,6 +77,7 @@ Other enhancements
 - :meth:`Series.map` now accepts an ``engine`` parameter to allow execution with a third-party execution engine (:issue:`61125`)
 - :meth:`Series.str.get_dummies` now accepts a  ``dtype`` parameter to specify the dtype of the resulting DataFrame (:issue:`47872`)
 - :meth:`pandas.concat` will raise a ``ValueError`` when ``ignore_index=True`` and ``keys`` is not ``None`` (:issue:`59274`)
+- :class:`Holiday` constructor argument ``days_of_week`` will  raise a ``ValueError`` when type is something other than ``None`` or ``tuple``
 - :py:class:`frozenset` elements in pandas objects are now natively printed (:issue:`60690`)
 - Add ``"delete_rows"`` option to ``if_exists`` argument in :meth:`DataFrame.to_sql` deleting all records of the table before inserting data (:issue:`37210`).
 - Added half-year offset classes :class:`HalfYearBegin`, :class:`HalfYearEnd`, :class:`BHalfYearBegin` and :class:`BHalfYearEnd` (:issue:`60928`)

pandas/tests/tseries/holiday/test_holiday.py

@@ -454,3 +454,10 @@ def test_exclude_date_value_error():
             Timestamp("2026-06-10"),
         ]
         Holiday("National Ice Tea Day", month=6, day=10, exclude_dates=exclude)
+
+
+def test_days_of_week_value_error():
+    msg = "days_of_week must be None or tuple."
+
+    with pytest.raises(ValueError, match=msg):
+        Holiday("World Blood Donor Day", month=6, day=14, days_of_week=[0, 1])

pandas/tseries/holiday.py

@@ -192,8 +192,9 @@ class from pandas.tseries.offsets, default None
         end_date : datetime-like, default None
             Last date the holiday is observed
         days_of_week : tuple of int or dateutil.relativedelta weekday strs, default None
-            Provide a tuple of days e.g  (0,1,2,3,) for Monday Through Thursday
+            Provide a tuple of days e.g  (0,1,2,3,) for Monday through Thursday
             Monday=0,..,Sunday=6
+            Only instances of the holiday included in days_of_week will be computed
         exclude_dates : DatetimeIndex or default None
             Specific dates to exclude e.g. skipping a specific year's holiday
 
@@ -258,7 +259,8 @@ class from pandas.tseries.offsets, default None
         )
         self.end_date = Timestamp(end_date) if end_date is not None else end_date
         self.observance = observance
-        assert days_of_week is None or type(days_of_week) == tuple
+        if not (days_of_week is None or isinstance(days_of_week, tuple)):
+            raise ValueError("days_of_week must be None or tuple.")
         self.days_of_week = days_of_week
         if not (exclude_dates is None or isinstance(exclude_dates, DatetimeIndex)):
             raise ValueError("exclude_dates must be None or of type DatetimeIndex.")