TYP: localization.py (#45065)

Author: mroeschke

pandas/_config/localization.py

@@ -3,16 +3,24 @@
 
 Name `localization` is chosen to avoid overlap with builtin `locale` module.
 """
+from __future__ import annotations
+
 from contextlib import contextmanager
 import locale
 import re
 import subprocess
+from typing import (
+    Callable,
+    Iterator,
+)
 
 from pandas._config.config import options
 
 
 @contextmanager
-def set_locale(new_locale, lc_var: int = locale.LC_ALL):
+def set_locale(
+    new_locale: str | tuple[str, str], lc_var: int = locale.LC_ALL
+) -> Iterator[str | tuple[str, str]]:
     """
     Context manager for temporarily setting a locale.
 
@@ -71,7 +79,7 @@ def can_set_locale(lc: str, lc_var: int = locale.LC_ALL) -> bool:
         return True
 
 
-def _valid_locales(locales, normalize):
+def _valid_locales(locales: list[str] | str, normalize: bool) -> list[str]:
     """
     Return a list of normalized locales that do not throw an ``Exception``
     when set.
@@ -98,11 +106,15 @@ def _valid_locales(locales, normalize):
     ]
 
 
-def _default_locale_getter():
+def _default_locale_getter() -> bytes:
     return subprocess.check_output(["locale -a"], shell=True)
 
 
-def get_locales(prefix=None, normalize=True, locale_getter=_default_locale_getter):
+def get_locales(
+    prefix: str | None = None,
+    normalize: bool = True,
+    locale_getter: Callable[[], bytes] = _default_locale_getter,
+) -> list[str] | None:
     """
     Get all the locales that are available on the system.
 
@@ -142,9 +154,9 @@ def get_locales(prefix=None, normalize=True, locale_getter=_default_locale_gette
         # raw_locales is "\n" separated list of locales
         # it may contain non-decodable parts, so split
         # extract what we can and then rejoin.
-        raw_locales = raw_locales.split(b"\n")
+        split_raw_locales = raw_locales.split(b"\n")
         out_locales = []
-        for x in raw_locales:
+        for x in split_raw_locales:
             try:
                 out_locales.append(str(x, encoding=options.display.encoding))
             except UnicodeError:

pandas/tests/indexes/datetimes/test_misc.py

@@ -191,8 +191,9 @@ def test_datetimeindex_accessors6(self):
         assert [d.weekofyear for d in dates] == expected
 
     # GH 12806
+    # error: Unsupported operand types for + ("List[None]" and "List[str]")
     @pytest.mark.parametrize(
-        "time_locale", [None] if tm.get_locales() is None else [None] + tm.get_locales()
+        "time_locale", [None] + (tm.get_locales() or [])  # type: ignore[operator]
     )
     def test_datetime_name_accessors(self, time_locale):
         # Test Monday -> Sunday and January -> December, in that sequence

pandas/tests/scalar/timestamp/test_timestamp.py

@@ -154,8 +154,9 @@ def check(value, equal):
         "data",
         [Timestamp("2017-08-28 23:00:00"), Timestamp("2017-08-28 23:00:00", tz="EST")],
     )
+    # error: Unsupported operand types for + ("List[None]" and "List[str]")
     @pytest.mark.parametrize(
-        "time_locale", [None] if tm.get_locales() is None else [None] + tm.get_locales()
+        "time_locale", [None] + (tm.get_locales() or [])  # type: ignore[operator]
     )
     def test_names(self, data, time_locale):
         # GH 17354

pandas/tests/series/accessors/test_dt_accessor.py

@@ -426,8 +426,9 @@ def test_dt_accessor_no_new_attributes(self):
         with pytest.raises(AttributeError, match="You cannot add any new attribute"):
             ser.dt.xlabel = "a"
 
+    # error: Unsupported operand types for + ("List[None]" and "List[str]")
     @pytest.mark.parametrize(
-        "time_locale", [None] if tm.get_locales() is None else [None] + tm.get_locales()
+        "time_locale", [None] + (tm.get_locales() or [])  # type: ignore[operator]
     )
     def test_dt_accessor_datetime_name_accessors(self, time_locale):
         # Test Monday -> Sunday and January -> December, in that sequence