diff --git a/GPy/kern/src/static.py b/GPy/kern/src/static.py
index ae6d06cb..18f7605f 100644
--- a/GPy/kern/src/static.py
+++ b/GPy/kern/src/static.py
@@ -104,10 +104,10 @@ class WhiteHeteroscedastic(Static):
         return 0.
 
     def K(self, X, X2=None):
-        if X2 is None and X.shape[0]==self.variance.shape[0]:
-            return np.eye(X.shape[0])*self.variance
+        if X2 is None and X.shape[0] == self.variance.shape[0]:
+            return np.eye(X.shape[0]) * self.variance
         else:
-            return np.zeros((X.shape[0], X2.shape[0]))
+            return 0.
 
     def psi2(self, Z, variational_posterior):
         return np.zeros((Z.shape[0], Z.shape[0]), dtype=np.float64)