From ed6085d07ce8feec99ad1e4d76b1d42b7192bfaf Mon Sep 17 00:00:00 2001
From: Grant Sanderson <grant@3blue1brown.com>
Date: Sat, 22 Feb 2020 13:19:51 -0800
Subject: [PATCH] Add replace_submobject

---
 manimlib/mobject/mobject.py | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/manimlib/mobject/mobject.py b/manimlib/mobject/mobject.py
index 0f10ad67..2b077542 100644
--- a/manimlib/mobject/mobject.py
+++ b/manimlib/mobject/mobject.py
@@ -137,6 +137,14 @@ class Mobject(Container):
         self.set_submobjects(list_update(mobjects, self.sub_mobjects))
         return self
 
+    def replace_submobject(self, index, new_submob):
+        old_submob = self.submobjects[index]
+        if self in old_submob.parents:
+            old_submob.parents.remove(self)
+        self.submobjects[index] = new_submob
+        self.assemble_family()
+        return self
+
     def set_submobjects(self, submobject_list):
         self.remove(*self.submobjects)
         self.add(*submobject_list)
@@ -1037,7 +1045,7 @@ class Mobject(Container):
 
     def push_self_into_submobjects(self):
         copy = self.deepcopy()
-        copy.submobjects.set_submobjects([])
+        copy.set_submobjects([])
         self.reset_points()
         self.add(copy)
         return self