diff --git a/src/one_to_many_with_data.rs b/src/one_to_many_with_data.rs
index 5987ed8..a41b993 100644
--- a/src/one_to_many_with_data.rs
+++ b/src/one_to_many_with_data.rs
@@ -1,4 +1,4 @@
-use std::collections::{BTreeMap, BTreeSet};
+use std::collections::BTreeMap;
 
 #[derive(Debug, Clone)]
 pub struct OneToManyUniqueBTreeMapWithData<Left, Right, RightData> {