From c0ec3160239bee9aefe8fd1ac37ddd2588f7a311 Mon Sep 17 00:00:00 2001
From: Markus Birth <mbirth@gmail.com>
Date: Tue, 16 Oct 2018 23:45:22 +0200
Subject: [PATCH] Use Python methods for ChkSum - speed bump.

---
 grmn/chksum.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/grmn/chksum.py b/grmn/chksum.py
index 1892705..8923c70 100644
--- a/grmn/chksum.py
+++ b/grmn/chksum.py
@@ -7,8 +7,7 @@ class ChkSum:
         self.last_byte = 0xff
 
     def add(self, data):
-        for c in data:
-            self.chksum += c
+        self.chksum += sum(bytearray(data))
         self.last_byte = data[-1]
         self.chksum &= 0xff