From ed25f5fefe5b60c28906b4d4f357c59524bcb663 Mon Sep 17 00:00:00 2001
From: user202729 <25191436+user202729@users.noreply.github.com>
Date: Tue, 4 Feb 2025 14:03:27 +0700
Subject: [PATCH] Undo adding is_empty to Parent and add it to FiniteWords

---
 src/sage/combinat/words/words.py | 13 +++++++++++++
 src/sage/structure/parent.pyx    |  7 -------
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/sage/combinat/words/words.py b/src/sage/combinat/words/words.py
index 8d6bb2a57fe..e9e79f1f4c0 100644
--- a/src/sage/combinat/words/words.py
+++ b/src/sage/combinat/words/words.py
@@ -350,6 +350,19 @@ def __init__(self, alphabet=None, category=None):
             category = category.Finite()
         super().__init__(alphabet, category)
 
+    def is_empty(self):
+        """
+        Return False, because the empty word is in the set.
+
+        TESTS::
+
+            sage: FiniteWords('ab').is_empty()
+            False
+            sage: FiniteWords([]).is_empty()
+            False
+        """
+        return False
+
     def cardinality(self):
         r"""
         Return the cardinality of this set.
diff --git a/src/sage/structure/parent.pyx b/src/sage/structure/parent.pyx
index cd0db7ac709..1dd2ae070ca 100644
--- a/src/sage/structure/parent.pyx
+++ b/src/sage/structure/parent.pyx
@@ -1235,13 +1235,6 @@ cdef class Parent(sage.structure.category_object.CategoryObject):
         """
         return True
 
-    def is_empty(self):
-        """
-        Default implementation of the method :meth:`is_empty`.
-        Delegates to :meth:`__bool__`.
-        """
-        return not bool(self)
-
     # Should be moved and merged into the EnumeratedSets() category (#12955)
     def __getitem__(self, n):
         """