diff --git a/src/important.cc b/src/important.cc
new file mode 100644
index 0000000..9c68461
--- /dev/null
+++ b/src/important.cc
@@ -0,0 +1,3 @@
+// Here we care if we find prohibited regexes.
+std::unique_ptr<int> add(int a, int b) {
+  return std::make_unique<int>(a + b);
+}