diff --git a/notebooks/exploring_explorer.livemd b/notebooks/exploring_explorer.livemd
index 41a0a8392..52c1b68e8 100644
--- a/notebooks/exploring_explorer.livemd
+++ b/notebooks/exploring_explorer.livemd
@@ -964,6 +964,7 @@ series contents, but every operation will be optimized and run only once.
 Remember those helpful error messages?
 
 ```elixir
+# Notice that the following typo is intentional here.
 DF.filter(df, cuontry == "BRAZIL")
 ```