diff --git a/spglm/iwls.py b/spglm/iwls.py
index 00e2018..543e3c4 100644
--- a/spglm/iwls.py
+++ b/spglm/iwls.py
@@ -108,7 +108,7 @@ def iwls(y, x, family, offset, y_fix,
     diff = 1.0e6
 
     if ini_betas is None:
-        betas = np.zeros((x.shape[1], 1), np.float)
+        betas = np.zeros((x.shape[1], 1))
     else:
         betas = ini_betas