diff --git a/src/utility/lib/CDFunctor.re b/src/utility/lib/CDFunctor.re
new file mode 100644
index 00000000..c6b823dd
--- /dev/null
+++ b/src/utility/lib/CDFunctor.re
@@ -0,0 +1,7 @@
+module type Config = {let shape: DistributionTypes.xyShape;};
+
+module Make = (Config: Config) => {
+  let validateHasLength = (): bool => Array.length(Config.shape.xs) > 0;
+  let validateSize = (): bool =>
+    Array.length(Config.shape.xs) == Array.length(Config.shape.ys);
+};
diff --git a/src/utility/lib/CDFunctor__Test.re b/src/utility/lib/CDFunctor__Test.re
new file mode 100644
index 00000000..e6399a8f
--- /dev/null
+++ b/src/utility/lib/CDFunctor__Test.re
@@ -0,0 +1,8 @@
+module CDFConfig = {
+  let shape: DistributionTypes.xyShape = {
+    xs: [|1., 4., 8.|],
+    ys: [|8., 9., 2.|],
+  };
+};
+
+module CDF = CDFunctor.Make(CDFConfig);