From aa5589ce90f65a68c73a9562738b95b629ce0e47 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Wed, 6 Mar 2024 11:46:12 -0800
Subject: [PATCH 01/10] PERF: RangeIndex.take with 1 value return RangeIndex

---
 pandas/core/indexes/range.py              |  8 +++++++-
 pandas/tests/indexes/ranges/test_range.py | 15 +++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/pandas/core/indexes/range.py b/pandas/core/indexes/range.py
index 09d635b53c482..76068c8ee901e 100644
--- a/pandas/core/indexes/range.py
+++ b/pandas/core/indexes/range.py
@@ -1260,4 +1260,10 @@ def take(  # type: ignore[override]
             if self.start != 0:
                 taken += self.start
 
-        return self._shallow_copy(taken, name=self.name)
+        if len(taken) == 1:
+            start = taken[0]
+            return self._simple_new(
+                range(start, start + self.step, self.step), name=self.name
+            )
+        else:
+            return self._shallow_copy(taken, name=self.name)
diff --git a/pandas/tests/indexes/ranges/test_range.py b/pandas/tests/indexes/ranges/test_range.py
index 898548d1cc4dc..2b81d4794627d 100644
--- a/pandas/tests/indexes/ranges/test_range.py
+++ b/pandas/tests/indexes/ranges/test_range.py
@@ -639,6 +639,21 @@ def test_take_return_rangeindex():
     tm.assert_index_equal(result, expected, exact=True)
 
 
+@pytest.mark.parametrize(
+    "rng, exp_rng",
+    [
+        [range(5), range(3, 4)],
+        [range(0, -10, -2), range(-6, -8, -2)],
+        [range(0, 10, 2), range(6, 8, 2)],
+    ],
+)
+def test_take_1_value_returns_rangeindex(rng, exp_rng):
+    ri = RangeIndex(rng, name="foo")
+    result = ri.take([3])
+    expected = RangeIndex(exp_rng, name="foo")
+    tm.assert_index_equal(result, expected, exact=True)
+
+
 def test_append_one_nonempty_preserve_step():
     expected = RangeIndex(0, -1, -1)
     result = RangeIndex(0).append([expected])

From 47af1ce9abaa3e112a995d10ecb76ae48ef4bbf5 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Wed, 6 Mar 2024 11:47:17 -0800
Subject: [PATCH 02/10] add issue number

---
 doc/source/whatsnew/v3.0.0.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v3.0.0.rst b/doc/source/whatsnew/v3.0.0.rst
index 7802ef4798659..8941af2a5b463 100644
--- a/doc/source/whatsnew/v3.0.0.rst
+++ b/doc/source/whatsnew/v3.0.0.rst
@@ -258,7 +258,7 @@ Performance improvements
 - Performance improvement in :meth:`RangeIndex.append` when appending the same index (:issue:`57252`)
 - Performance improvement in :meth:`RangeIndex.join` returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57651`)
 - Performance improvement in :meth:`RangeIndex.reindex` returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57647`)
-- Performance improvement in :meth:`RangeIndex.take` returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57445`)
+- Performance improvement in :meth:`RangeIndex.take` returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57445`, :issue:`57752`)
 - Performance improvement in ``DataFrameGroupBy.__len__`` and ``SeriesGroupBy.__len__`` (:issue:`57595`)
 - Performance improvement in indexing operations for string dtypes (:issue:`56997`)
 

From e7e0fcba0cf6fb2f94ceb5d9b8ae8ec4b5131f39 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Wed, 6 Mar 2024 13:08:26 -0800
Subject: [PATCH 03/10] Move to _shallow_copy, support empty join as well

---
 doc/source/whatsnew/v3.0.0.rst            |  4 +--
 pandas/core/indexes/base.py               |  1 -
 pandas/core/indexes/range.py              | 44 +++++++++++++++--------
 pandas/tests/indexes/ranges/test_join.py  |  8 ++++-
 pandas/tests/indexes/ranges/test_range.py | 20 +++++++++++
 5 files changed, 58 insertions(+), 19 deletions(-)

diff --git a/doc/source/whatsnew/v3.0.0.rst b/doc/source/whatsnew/v3.0.0.rst
index 8941af2a5b463..70fe03000290b 100644
--- a/doc/source/whatsnew/v3.0.0.rst
+++ b/doc/source/whatsnew/v3.0.0.rst
@@ -256,8 +256,8 @@ Performance improvements
 - Performance improvement in :meth:`MultiIndex.equals` for equal length indexes (:issue:`56990`)
 - Performance improvement in :meth:`RangeIndex.__getitem__` with a boolean mask returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57588`)
 - Performance improvement in :meth:`RangeIndex.append` when appending the same index (:issue:`57252`)
-- Performance improvement in :meth:`RangeIndex.join` returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57651`)
-- Performance improvement in :meth:`RangeIndex.reindex` returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57647`)
+- Performance improvement in :meth:`RangeIndex.join` returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57651`, :issue:`57752`)
+- Performance improvement in :meth:`RangeIndex.reindex` returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57647`, :issue:`57752`)
 - Performance improvement in :meth:`RangeIndex.take` returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57445`, :issue:`57752`)
 - Performance improvement in ``DataFrameGroupBy.__len__`` and ``SeriesGroupBy.__len__`` (:issue:`57595`)
 - Performance improvement in indexing operations for string dtypes (:issue:`56997`)
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index c72c5fa019bd7..4e5cc986b7325 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -4241,7 +4241,6 @@ def join(
 
         return self._join_via_get_indexer(other, how, sort)
 
-    @final
     def _join_empty(
         self, other: Index, how: JoinHow, sort: bool
     ) -> tuple[Index, npt.NDArray[np.intp] | None, npt.NDArray[np.intp] | None]:
diff --git a/pandas/core/indexes/range.py b/pandas/core/indexes/range.py
index 76068c8ee901e..573bd6cf14bcb 100644
--- a/pandas/core/indexes/range.py
+++ b/pandas/core/indexes/range.py
@@ -472,18 +472,31 @@ def _shallow_copy(self, values, name: Hashable = no_default):
 
         if values.dtype.kind == "f":
             return Index(values, name=name, dtype=np.float64)
-        if values.dtype.kind == "i" and values.ndim == 1 and len(values) > 1:
+        if values.dtype.kind == "i" and values.ndim == 1:
             # GH 46675 & 43885: If values is equally spaced, return a
             # more memory-compact RangeIndex instead of Index with 64-bit dtype
+            if len(values) == 0:
+                return type(self)._simple_new(_empty_range, name=self.name)
+            elif len(values) == 1:
+                start = values[0]
+                new_range = range(start, start + self.step, self.step)
+                return type(self)._simple_new(new_range, name=self.name)
             diff = values[1] - values[0]
             if not missing.isna(diff) and diff != 0:
-                maybe_range_indexer, remainder = np.divmod(values - values[0], diff)
-                if (
-                    lib.is_range_indexer(maybe_range_indexer, len(maybe_range_indexer))
-                    and not remainder.any()
-                ):
+                if len(values) == 2:
+                    # Can skip is_range_indexer check
                     new_range = range(values[0], values[-1] + diff, diff)
-                    return type(self)._simple_new(new_range, name=name)
+                    return type(self)._simple_new(new_range, name=self.name)
+                else:
+                    maybe_range_indexer, remainder = np.divmod(values - values[0], diff)
+                    if (
+                        lib.is_range_indexer(
+                            maybe_range_indexer, len(maybe_range_indexer)
+                        )
+                        and not remainder.any()
+                    ):
+                        new_range = range(values[0], values[-1] + diff, diff)
+                        return type(self)._simple_new(new_range, name=name)
         return self._constructor._simple_new(values, name=name)
 
     def _view(self) -> Self:
@@ -897,12 +910,19 @@ def symmetric_difference(
             result = result.rename(result_name)
         return result
 
+    def _join_empty(
+        self, other: Index, how: JoinHow, sort: bool
+    ) -> tuple[Index, npt.NDArray[np.intp] | None, npt.NDArray[np.intp] | None]:
+        if other.dtype.kind == "i":
+            other = self._shallow_copy(other._values, name=other.name)
+        return super()._join_empty(other, how=how, sort=sort)
+
     def _join_monotonic(
         self, other: Index, how: JoinHow = "left"
     ) -> tuple[Index, npt.NDArray[np.intp] | None, npt.NDArray[np.intp] | None]:
         # This currently only gets called for the monotonic increasing case
         if not isinstance(other, type(self)):
-            maybe_ri = self._shallow_copy(other._values)
+            maybe_ri = self._shallow_copy(other._values, name=other.name)
             if not isinstance(maybe_ri, type(self)):
                 return super()._join_monotonic(other, how=how)
             other = maybe_ri
@@ -1260,10 +1280,4 @@ def take(  # type: ignore[override]
             if self.start != 0:
                 taken += self.start
 
-        if len(taken) == 1:
-            start = taken[0]
-            return self._simple_new(
-                range(start, start + self.step, self.step), name=self.name
-            )
-        else:
-            return self._shallow_copy(taken, name=self.name)
+        return self._shallow_copy(taken, name=self.name)
diff --git a/pandas/tests/indexes/ranges/test_join.py b/pandas/tests/indexes/ranges/test_join.py
index ca3af607c0a38..09db30b1d4c51 100644
--- a/pandas/tests/indexes/ranges/test_join.py
+++ b/pandas/tests/indexes/ranges/test_join.py
@@ -207,9 +207,15 @@ def test_join_self(self, join_type):
             [-1, -1, 0, 1],
             "outer",
         ],
+        [RangeIndex(2), RangeIndex(0), RangeIndex(2), None, [-1, -1], "left"],
+        [RangeIndex(2), RangeIndex(0), RangeIndex(0), [], None, "right"],
+        [RangeIndex(2), RangeIndex(0), RangeIndex(0), [], None, "inner"],
+        [RangeIndex(2), RangeIndex(0), RangeIndex(2), None, [-1, -1], "outer"],
     ],
 )
-@pytest.mark.parametrize("right_type", [RangeIndex, lambda x: Index(list(x))])
+@pytest.mark.parametrize(
+    "right_type", [RangeIndex, lambda x: Index(list(x), dtype=x.dtype)]
+)
 def test_join_preserves_rangeindex(
     left, right, expected, expected_lidx, expected_ridx, how, right_type
 ):
diff --git a/pandas/tests/indexes/ranges/test_range.py b/pandas/tests/indexes/ranges/test_range.py
index 2b81d4794627d..528315078277d 100644
--- a/pandas/tests/indexes/ranges/test_range.py
+++ b/pandas/tests/indexes/ranges/test_range.py
@@ -608,6 +608,26 @@ def test_range_index_rsub_by_const(self):
         tm.assert_index_equal(result, expected)
 
 
+def test_reindex_1_value_returns_rangeindex():
+    ri = RangeIndex(0, 10, 2, name="foo")
+    result, result_indexer = ri.reindex([2])
+    expected = RangeIndex(2, 4, 2, name="foo")
+    tm.assert_index_equal(result, expected, exact=True)
+
+    expected_indexer = np.array([1], dtype=np.intp)
+    tm.assert_numpy_array_equal(result_indexer, expected_indexer)
+
+
+def test_reindex_empty_returns_rangeindex():
+    ri = RangeIndex(0, 10, 2, name="foo")
+    result, result_indexer = ri.reindex([])
+    expected = RangeIndex(0, 0, 2, name="foo")
+    tm.assert_index_equal(result, expected, exact=True)
+
+    expected_indexer = np.array([], dtype=np.intp)
+    tm.assert_numpy_array_equal(result_indexer, expected_indexer)
+
+
 def test_reindex_returns_rangeindex():
     ri = RangeIndex(2, name="foo")
     result, result_indexer = ri.reindex([1, 2, 3])

From 67f19987a86d11d046e4d7f63d58caca3b217a42 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Wed, 6 Mar 2024 13:09:59 -0800
Subject: [PATCH 04/10] Fix self.name

---
 pandas/core/indexes/range.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/pandas/core/indexes/range.py b/pandas/core/indexes/range.py
index 573bd6cf14bcb..4fa075d10c9e0 100644
--- a/pandas/core/indexes/range.py
+++ b/pandas/core/indexes/range.py
@@ -476,17 +476,17 @@ def _shallow_copy(self, values, name: Hashable = no_default):
             # GH 46675 & 43885: If values is equally spaced, return a
             # more memory-compact RangeIndex instead of Index with 64-bit dtype
             if len(values) == 0:
-                return type(self)._simple_new(_empty_range, name=self.name)
+                return type(self)._simple_new(_empty_range, name=name)
             elif len(values) == 1:
                 start = values[0]
                 new_range = range(start, start + self.step, self.step)
-                return type(self)._simple_new(new_range, name=self.name)
+                return type(self)._simple_new(new_range, name=name)
             diff = values[1] - values[0]
             if not missing.isna(diff) and diff != 0:
                 if len(values) == 2:
                     # Can skip is_range_indexer check
                     new_range = range(values[0], values[-1] + diff, diff)
-                    return type(self)._simple_new(new_range, name=self.name)
+                    return type(self)._simple_new(new_range, name=name)
                 else:
                     maybe_range_indexer, remainder = np.divmod(values - values[0], diff)
                     if (

From 2cc41fc25fc245cf4cb96716685b5e19a770f719 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Wed, 6 Mar 2024 13:55:15 -0800
Subject: [PATCH 05/10] FIx error message

---
 pandas/tests/indexing/test_loc.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/tests/indexing/test_loc.py b/pandas/tests/indexing/test_loc.py
index 9c33d15c01cd6..61a3a7fbe87f2 100644
--- a/pandas/tests/indexing/test_loc.py
+++ b/pandas/tests/indexing/test_loc.py
@@ -508,7 +508,7 @@ def test_loc_getitem_list_with_fail(self):
 
         s.loc[[2]]
 
-        msg = f"\"None of [Index([3], dtype='{np.dtype(int)}')] are in the [index]"
+        msg = "None of [RangeIndex(start=3, stop=4, step=1)] are in the [index]"
         with pytest.raises(KeyError, match=re.escape(msg)):
             s.loc[[3]]
 

From c7da6acc720613e6494868ea0e87a40db4d6e280 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Wed, 6 Mar 2024 15:41:44 -0800
Subject: [PATCH 06/10] Fix hdf test

---
 pandas/tests/io/pytables/test_append.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pandas/tests/io/pytables/test_append.py b/pandas/tests/io/pytables/test_append.py
index 529d6d789596f..72abbcec63357 100644
--- a/pandas/tests/io/pytables/test_append.py
+++ b/pandas/tests/io/pytables/test_append.py
@@ -967,6 +967,8 @@ def test_append_to_multiple_min_itemsize(setup_path):
         }
     )
     expected = df.iloc[[0]]
+    # Reading/writing RangeIndex info is not supported yet
+    expected.index = Index(list(range(len(expected.index))))
 
     with ensure_clean_store(setup_path) as store:
         store.append_to_multiple(

From 028fbd4d8944d0bd5a724c8a41f5ace9fc500110 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Thu, 7 Mar 2024 13:12:19 -0800
Subject: [PATCH 07/10] PERF: RangeIndex.__getitem__ with integers return
 RangeIndex

---
 doc/source/whatsnew/v3.0.0.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v3.0.0.rst b/doc/source/whatsnew/v3.0.0.rst
index 85570cd4a6744..8408f609bdc99 100644
--- a/doc/source/whatsnew/v3.0.0.rst
+++ b/doc/source/whatsnew/v3.0.0.rst
@@ -255,7 +255,7 @@ Performance improvements
 - Performance improvement in :meth:`Index.join` by propagating cached attributes in cases where the result matches one of the inputs (:issue:`57023`)
 - Performance improvement in :meth:`Index.take` when ``indices`` is a full range indexer from zero to length of index (:issue:`56806`)
 - Performance improvement in :meth:`MultiIndex.equals` for equal length indexes (:issue:`56990`)
-- Performance improvement in :meth:`RangeIndex.__getitem__` with a boolean mask returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57588`)
+- Performance improvement in :meth:`RangeIndex.__getitem__` with a boolean mask or integers returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57588`)
 - Performance improvement in :meth:`RangeIndex.append` when appending the same index (:issue:`57252`)
 - Performance improvement in :meth:`RangeIndex.join` returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57651`, :issue:`57752`)
 - Performance improvement in :meth:`RangeIndex.reindex` returning a :class:`RangeIndex` instead of a :class:`Index` when possible. (:issue:`57647`, :issue:`57752`)

From ccd781d93825816a6c0c940885b43fcccc1c2b47 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Thu, 7 Mar 2024 13:12:29 -0800
Subject: [PATCH 08/10] PERF: RangeIndex.__getitem__ with integers return
 RangeIndex

---
 pandas/core/indexes/range.py              | 14 +++++++-------
 pandas/tests/indexes/ranges/test_range.py | 22 ++++++++++++++++++++++
 2 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/pandas/core/indexes/range.py b/pandas/core/indexes/range.py
index fcb47de2b3c0d..4c6513e7a0fca 100644
--- a/pandas/core/indexes/range.py
+++ b/pandas/core/indexes/range.py
@@ -1117,17 +1117,17 @@ def __getitem__(self, key):
             )
         elif com.is_bool_indexer(key):
             if isinstance(getattr(key, "dtype", None), ExtensionDtype):
-                np_key = key.to_numpy(dtype=bool, na_value=False)
+                key = key.to_numpy(dtype=bool, na_value=False)
             else:
-                np_key = np.asarray(key, dtype=bool)
-            check_array_indexer(self._range, np_key)  # type: ignore[arg-type]
+                key = np.asarray(key, dtype=bool)
+            check_array_indexer(self._range, key)  # type: ignore[arg-type]
             # Short circuit potential _shallow_copy check
-            if np_key.all():
+            if key.all():
                 return self._simple_new(self._range, name=self.name)
-            elif not np_key.any():
+            elif not key.any():
                 return self._simple_new(_empty_range, name=self.name)
-            return self.take(np.flatnonzero(np_key))
-        return super().__getitem__(key)
+            key = np.flatnonzero(key)
+        return self.take(key)
 
     def _getitem_slice(self, slobj: slice) -> Self:
         """
diff --git a/pandas/tests/indexes/ranges/test_range.py b/pandas/tests/indexes/ranges/test_range.py
index d99ba1b624775..3040b4c13dc17 100644
--- a/pandas/tests/indexes/ranges/test_range.py
+++ b/pandas/tests/indexes/ranges/test_range.py
@@ -730,3 +730,25 @@ def test_getitem_boolmask_wrong_length():
     ri = RangeIndex(4, name="foo")
     with pytest.raises(IndexError, match="Boolean index has wrong length"):
         ri[[True]]
+
+
+def test_getitem_integers_return_rangeindex():
+    result = RangeIndex(0, 10, 2, name="foo")[[0, -1]]
+    expected = RangeIndex(start=0, stop=16, step=8, name="foo")
+    tm.assert_index_equal(result, expected, exact=True)
+
+    result = RangeIndex(0, 10, 2, name="foo")[[3]]
+    expected = RangeIndex(start=6, stop=8, step=2, name="foo")
+    tm.assert_index_equal(result, expected, exact=True)
+
+
+def test_getitem_empty_return_rangeindex():
+    result = RangeIndex(0, 10, 2, name="foo")[[]]
+    expected = RangeIndex(start=0, stop=0, step=1, name="foo")
+    tm.assert_index_equal(result, expected, exact=True)
+
+
+def test_getitem_integers_return_index():
+    result = RangeIndex(0, 10, 2, name="foo")[[0, 1, -1]]
+    expected = Index([0, 2, 8], dtype="int64", name="foo")
+    tm.assert_index_equal(result, expected)

From 09b9445ba5f04cc1c18bdaa3481dc071eaf3dd41 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Thu, 7 Mar 2024 14:00:23 -0800
Subject: [PATCH 09/10] Handle ellipse

---
 pandas/core/indexes/range.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/pandas/core/indexes/range.py b/pandas/core/indexes/range.py
index 4c6513e7a0fca..22b3de199083c 100644
--- a/pandas/core/indexes/range.py
+++ b/pandas/core/indexes/range.py
@@ -1098,6 +1098,8 @@ def __getitem__(self, key):
         """
         Conserve RangeIndex type for scalar and slice keys.
         """
+        if key is Ellipsis:
+            key = slice(None)
         if isinstance(key, slice):
             return self._getitem_slice(key)
         elif is_integer(key):
@@ -1127,7 +1129,11 @@ def __getitem__(self, key):
             elif not key.any():
                 return self._simple_new(_empty_range, name=self.name)
             key = np.flatnonzero(key)
-        return self.take(key)
+        try:
+            return self.take(key)
+        except TypeError:
+            # Have Index.__getitem__ raise its exception
+            return super().__getitem__(key)
 
     def _getitem_slice(self, slobj: slice) -> Self:
         """

From bfa25bac586158f32aab60817bff18c8c851a269 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Thu, 7 Mar 2024 14:20:05 -0800
Subject: [PATCH 10/10] Catch ValueError

---
 pandas/core/indexes/range.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/pandas/core/indexes/range.py b/pandas/core/indexes/range.py
index 22b3de199083c..3fc3f7b4d50bb 100644
--- a/pandas/core/indexes/range.py
+++ b/pandas/core/indexes/range.py
@@ -1131,8 +1131,7 @@ def __getitem__(self, key):
             key = np.flatnonzero(key)
         try:
             return self.take(key)
-        except TypeError:
-            # Have Index.__getitem__ raise its exception
+        except (TypeError, ValueError):
             return super().__getitem__(key)
 
     def _getitem_slice(self, slobj: slice) -> Self: