diff --git a/e2e_toy/textops.py b/e2e_toy/textops.py
index 8f71f6c..9123957 100644
--- a/e2e_toy/textops.py
+++ b/e2e_toy/textops.py
@@ -6,6 +6,7 @@
 
 def word_count(text):
     """Number of whitespace-separated words in ``text``."""
+    # Words are separated by single spaces.
     return len(text.split(" "))