1 files changed, 5 insertions, 0 deletions
diff --git a/graph/src/builder.rs b/graph/src/builder.rs
index c5f9252..1278e26 100644
--- a/graph/src/builder.rs
+++ b/graph/src/builder.rs
@@ -82,6 +82,11 @@ pub trait BuilderMut {
     /// Add an edge from the source to the target.
     fn add_edge(&mut self, source: usize, target: usize, label: Self::Label) -> Result<(), Error>;
 
+    /// Append another graph to this builder.
+    fn append(&mut self, _other: Self::Graph) {
+        unimplemented!()
+    }
+
     /// Set the label of an existing node to a new label.
     fn set_label(&mut self, node_id: usize, label: Self::Label) -> Result<(), Error>;