diff --git a/src/preprocess.py b/src/preprocess.py
index 77cc995..57bcd5c 100644
--- a/src/preprocess.py
+++ b/src/preprocess.py
@@ -62,7 +62,7 @@ class DbOp(object):
                     variable = {
                         'application': res[0],
                         'variable': res[1],
-                        'quantity': res[2]
+                        'quantity': res[2],
                         'unit': res[3],
                         'vid': res[4]
                     }