diff --git a/simple_functions/functions1.py b/simple_functions/functions1.py
index 8c63a4d..57bcd8e 100644
--- a/simple_functions/functions1.py
+++ b/simple_functions/functions1.py
@@ -5,5 +5,5 @@
 def my_sum(iterable):
     tot = 0
     for i in iterable:
-        tot += i
+        tot -= i
     return tot
diff --git a/test1.txt b/test1.txt
new file mode 100644
index 0000000..12563d0
--- /dev/null
+++ b/test1.txt
@@ -0,0 +1 @@
+a test
\ No newline at end of file