Small changes.

src/model.rs

@@ -38,7 +38,7 @@ impl BinaryModel {
 
     pub fn add_item(&mut self, name: &str, kernel: Box<dyn Kernel>) {
         if self.storage.contains_key(name) {
-            // raise ValueError("item '{}' already added".format(name))
+            panic!("item '{}' already added", name);
         }
 
         self.storage.insert(
@@ -49,7 +49,7 @@ impl BinaryModel {
 
     pub fn observe(&mut self, winners: &[&str], losers: &[&str], t: f64) {
         if t < self.last_t {
-            // raise ValueError("observations must be added in chronological order")
+            panic!("observations must be added in chronological order");
         }
 
         let mut elems = self.process_items(winners, 1.0);
@@ -66,9 +66,11 @@ impl BinaryModel {
 
         self.observations.push(obs);
 
+        /*
         for (item, _) in elems {
-            // item.link_observation(obs)
+            item.link_observation(obs)
         }
+        */
 
         self.last_t = t;
     }