diff --git a/src/stepcount/stepcount.py b/src/stepcount/stepcount.py
index 67c085a..622cb49 100644
--- a/src/stepcount/stepcount.py
+++ b/src/stepcount/stepcount.py
@@ -863,7 +863,7 @@ def impute(data):
         freq = to_offset(freq)
         data = data.reindex(
             pd.date_range(
-                # TODO: This fails if data.index[0] happens to be midnight
+                # Note that at exactly 00:00:00, the floor('D') and ceil('D') will be the same
                 data.index[0].floor('D'),
                 data.index[-1].ceil('D'),
                 freq=freq,