diff --git a/src/fermion_operator.rs b/src/fermion_operator.rs
index f91e0ca87..edeeba891 100644
--- a/src/fermion_operator.rs
+++ b/src/fermion_operator.rs
@@ -30,10 +30,10 @@ impl KeysIterator {
 
     fn __next__(&mut self) -> Option<PyObject> {
         Python::with_gil(|py| {
-            return self
+            self
                 .keys
                 .next()
-                .map(|vec| PyTuple::new_bound(py, &vec).to_object(py));
+                .map(|vec| PyTuple::new_bound(py, &vec).to_object(py))
         })
     }
 }