diff --git a/todo_completion b/todo_completion
index 5e5a0e2..0d19e2a 100644
--- a/todo_completion
+++ b/todo_completion
@@ -1,3 +1,6 @@
+#!/bin/bash source-this-script
+[ "$BASH_VERSION" ] || return
+
 _todo()
 {
     local cur prev opts