From fe82598f27b7c79a4b9d12c7ed3216acdb31f6fe Mon Sep 17 00:00:00 2001
From: dangotbanned <125183946+dangotbanned@users.noreply.github.com>
Date: Fri, 14 Feb 2025 17:41:51 +0000
Subject: [PATCH 1/2] chore(typing): resolve time unit/zone `set` invariance

---
 narwhals/utils.py | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/narwhals/utils.py b/narwhals/utils.py
index c8615ab92..5531e3011 100644
--- a/narwhals/utils.py
+++ b/narwhals/utils.py
@@ -39,6 +39,7 @@
 
 if TYPE_CHECKING:
     from types import ModuleType
+    from typing import AbstractSet
     from typing import Protocol
 
     import pandas as pd
@@ -1241,15 +1242,15 @@ def check_column_names_are_unique(columns: list[str]) -> None:
 def _parse_time_unit_and_time_zone(
     time_unit: TimeUnit | Iterable[TimeUnit] | None,
     time_zone: str | timezone | Iterable[str | timezone | None] | None,
-) -> tuple[set[str], set[str | None]]:
-    time_units = (
+) -> tuple[set[TimeUnit], AbstractSet[str | None]]:
+    time_units: set[TimeUnit] = (
         {"ms", "us", "ns", "s"}
         if time_unit is None
         else {time_unit}
         if isinstance(time_unit, str)
         else set(time_unit)
     )
-    time_zones: set[str | None] = (
+    time_zones: AbstractSet[str | None] = (
         {None}
         if time_zone is None
         else {str(time_zone)}
@@ -1262,8 +1263,8 @@ def _parse_time_unit_and_time_zone(
 def dtype_matches_time_unit_and_time_zone(
     dtype: DType,
     dtypes: DTypes,
-    time_units: set[str],
-    time_zones: set[str | None],
+    time_units: set[TimeUnit],
+    time_zones: AbstractSet[str | None],
 ) -> bool:
     return (
         (dtype == dtypes.Datetime)

From b38403c0ecad54e39d6a471861412724a7313b26 Mon Sep 17 00:00:00 2001
From: dangotbanned <125183946+dangotbanned@users.noreply.github.com>
Date: Sat, 15 Feb 2025 10:48:15 +0000
Subject: [PATCH 2/2] refactor(typing): alias `AbstractSet` and consistently
 use `Set`

- https://github.com/narwhals-dev/narwhals/pull/2012#discussion_r1957088388
- https://docs.python.org/3/library/typing.html#typing.AbstractSet
---
 narwhals/utils.py | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/narwhals/utils.py b/narwhals/utils.py
index d2f3cbb87..96f912cd5 100644
--- a/narwhals/utils.py
+++ b/narwhals/utils.py
@@ -40,7 +40,7 @@
 
 if TYPE_CHECKING:
     from types import ModuleType
-    from typing import AbstractSet
+    from typing import AbstractSet as Set
     from typing import Protocol
 
     import pandas as pd
@@ -1243,15 +1243,15 @@ def check_column_names_are_unique(columns: list[str]) -> None:
 def _parse_time_unit_and_time_zone(
     time_unit: TimeUnit | Iterable[TimeUnit] | None,
     time_zone: str | timezone | Iterable[str | timezone | None] | None,
-) -> tuple[set[TimeUnit], AbstractSet[str | None]]:
-    time_units: set[TimeUnit] = (
+) -> tuple[Set[TimeUnit], Set[str | None]]:
+    time_units: Set[TimeUnit] = (
         {"ms", "us", "ns", "s"}
         if time_unit is None
         else {time_unit}
         if isinstance(time_unit, str)
         else set(time_unit)
     )
-    time_zones: AbstractSet[str | None] = (
+    time_zones: Set[str | None] = (
         {None}
         if time_zone is None
         else {str(time_zone)}
@@ -1262,10 +1262,7 @@ def _parse_time_unit_and_time_zone(
 
 
 def dtype_matches_time_unit_and_time_zone(
-    dtype: DType,
-    dtypes: DTypes,
-    time_units: set[TimeUnit],
-    time_zones: AbstractSet[str | None],
+    dtype: DType, dtypes: DTypes, time_units: Set[TimeUnit], time_zones: Set[str | None]
 ) -> bool:
     return (
         (dtype == dtypes.Datetime)