more fixes

nifty/data_objects/random.py

@@ -32,6 +32,9 @@ class Random(object):
 
     @staticmethod
     def normal(dtype, shape, mean=0., std=1.):
+        if not (np.issubdtype(dtype, np.floating) or
+                np.issubdtype(dtype, np.complexfloating)):
+            raise TypeError("dtype must be float or complex")
         if not np.isscalar(mean) or not np.isscalar(std):
             raise TypeError("mean and std must be scalars")
         if np.issubdtype(type(std), np.complexfloating):