--- a/src/ast_dump.rs
+++ b/src/ast_dump.rs
@@ -265,7 +265,19 @@ impl stmt {
             stmt::Break => format!("{}break", current_indent),
             stmt::Delete(targets) => format!("{}del {}", current_indent, vec_to_strings_vec(targets).join(", ")),
             stmt::Pass => format!("{}pass", current_indent),
-            stmt::Continue => format!("{}continue", current_indent)
+            stmt::Continue => format!("{}continue", current_indent),
+            stmt::Assert(test, msg) => {
+                format!("{}assert {}{}",
+                    current_indent,
+                    test.to_string(),
+                    {
+                        match msg {
+                            Some(msg) => format!(", {}", msg.to_string()),
+                            None => format!("")
+                        }
+                    }
+                )
+            }
         }
     }
 }