diff --git a/src/lib.rs b/src/lib.rs
index 7d12d9a..a5704f3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,5 @@
+mod multithreading;
+
 pub fn add(left: usize, right: usize) -> usize {
     left + right
 }