diff --git a/module3/exo1/influenza-like-illness-analysis.org b/module3/exo1/influenza-like-illness-analysis.org
index d4f87cd78db3f701152bfe8f591546ea08388556..5befa77bdd270d1adedc696514f7b8f0a9880cac 100644
--- a/module3/exo1/influenza-like-illness-analysis.org
+++ b/module3/exo1/influenza-like-illness-analysis.org
@@ -92,6 +92,7 @@ table[:5]
 
 ** Checking for missing data
 Unfortunately there are many ways to indicate the absence of a data value in a dataset. Here we check for a common one: empty fields. For completeness, we should also look for non-numerical data in numerical columns. We don't do this here, but checks in later processing steps would catch such anomalies.
+
 We make a new dataset without the lines that contain empty fields. We print those lines to preserve a trace of their contents.
 
 #+BEGIN_SRC python :results output  :exports both
@@ -135,6 +136,7 @@ for week, inc in data:
 #+END_SRC
 
 No problem - fine!
+
 ** Date conversion
 In order to facilitate the subsequent treatment, we replace the ISO week numbers by the dates of each week's Monday. This is also a good occasion to sort the lines by increasing data, and to convert the incidences from strings to integers.