diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index ed694bd..05e969e 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -55,3 +55,7 @@ sudo make install
 #  Run the tests against the installed extension.
 make test
 ```
+
+## Submitting contributions
+
+Before opening a pull request (or submitting a contribution) you will need to sign a Contributor License Agreement (CLA) before making a submission, [learn more here](https://carto.com/contributions).
diff --git a/src/py/crankshaft/crankshaft/clustering/moran.py b/src/py/crankshaft/crankshaft/clustering/moran.py
index a42a981..0e12e3f 100644
--- a/src/py/crankshaft/crankshaft/clustering/moran.py
+++ b/src/py/crankshaft/crankshaft/clustering/moran.py
@@ -88,7 +88,7 @@ class Moran:
         """
         params = OrderedDict([("id_col", id_col),
                               ("attr1", numerator),
-                              ("attr2", denominator)
+                              ("attr2", denominator),
                               ("geom_col", geom_col),
                               ("subquery", subquery),
                               ("num_ngbrs", num_ngbrs)])