Run cargo fmt

src/data/arena.rs

@@ -60,7 +60,7 @@ impl Default for Index {
 
 impl IndexedData for Index {
     fn default() -> Self {
-       Default::default()
+        Default::default()
     }
 
     fn index(&self) -> usize {

src/data/graph.rs

@@ -125,7 +125,7 @@ impl<E> Edge<E> {
     }
 }
 
-#[derive(Clone, Debug,Default)]
+#[derive(Clone, Debug, Default)]
 #[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
 pub struct Graph<N, E> {
     pub(crate) nodes: Vec<Node<N>>,