diff --git a/src/io/in.rs b/src/io/in.rs
new file mode 100644
index 0000000..e69de29
diff --git a/src/io.rs b/src/io/mod.rs
similarity index 100%
rename from src/io.rs
rename to src/io/mod.rs
diff --git a/src/io/out.rs b/src/io/out.rs
new file mode 100644
index 0000000..e69de29