diff --git a/receiver/src/keyboard.rs b/receiver/src/keyboard.rs
index d6d7e01..72fcf8b 100644
--- a/receiver/src/keyboard.rs
+++ b/receiver/src/keyboard.rs
@@ -2,13 +2,15 @@
 use enigo::{KeyboardControllable};
 
 #[cfg(target_family = "unix")]
-pub fn type_text(text: &str) {
+pub fn type_text(text: &str) -> Result<(),()> {
     enigo::Enigo::default().key_sequence(text);
+    Ok(())
 }
 
 #[cfg(target_family = "unix")]
-pub fn click_tab() {
+pub fn click_tab() -> Result<(),()> {
     enigo::Enigo::default().key_click(enigo::Key::Tab);
+    Ok(())
 }
 
 #[cfg(target_family = "windows")]
diff --git a/receiver/src/main.rs b/receiver/src/main.rs
index 4516dff..bd5400d 100644
--- a/receiver/src/main.rs
+++ b/receiver/src/main.rs
@@ -81,7 +81,7 @@ fn main() {
     let password = "test";
     let broker_domain = "broker.emqx.io";
 
-    let mut c = comm::Comm::new(&broker_domain, &password, handle_time).unwrap();
+    let c = comm::Comm::new(&broker_domain, &password, handle_time).unwrap();
 
     //Gui::run(Settings::default());