From 001139b18d9c02d62acaa8bc61c9902e8e3f8ec0 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Fri, 29 Jul 2022 11:07:48 +0100
Subject: [PATCH] fix for 3.7

---
 src/textual/dom.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/textual/dom.py b/src/textual/dom.py
index 3bda0e690..f9a77a2e1 100644
--- a/src/textual/dom.py
+++ b/src/textual/dom.py
@@ -356,9 +356,9 @@ class DOMNode(MessagePump):
 
         # TODO: Feels like there may be opportunity for caching here.
 
-        style = sum(
-            [node.styles.text_style for node in reversed(self.ancestors)], start=Style()
-        )
+        style = Style()
+        for node in reversed(self.ancestors):
+            style += node.styles.text_style
         return style
 
     @property