diff --git a/python/obitools3/dms/dms.pyx b/python/obitools3/dms/dms.pyx
index 5ab46cf..2392c66 100644
--- a/python/obitools3/dms/dms.pyx
+++ b/python/obitools3/dms/dms.pyx
@@ -38,7 +38,7 @@ cdef class DMS(OBIWrapper):
         pointer = obi_create_dms(<const_char_p> dms_name_b)      
         if pointer == NULL :
             raise Exception("Failed creating an OBIDMS")
-        dms = OBIWrapper.new(DMS, pointer)
+        dms = OBIWrapper.new_wrapper(DMS, pointer)
         return dms
 
 
@@ -50,7 +50,7 @@ cdef class DMS(OBIWrapper):
         pointer = obi_open_dms(<const_char_p> dms_name_b)      
         if pointer == NULL :
             raise Exception("Failed opening an OBIDMS")
-        dms = OBIWrapper.new(DMS, pointer)
+        dms = OBIWrapper.new_wrapper(DMS, pointer)
         return dms
    
 
@@ -60,9 +60,10 @@ cdef class DMS(OBIWrapper):
         cdef DMS dms
         cdef bytes dms_name_b = tobytes(dms_name)
         pointer = obi_test_open_dms(<const_char_p> dms_name_b)      
-        if pointer == NULL :
-            raise Exception("Failed opening an OBIDMS")
-        dms = OBIWrapper.new(DMS, pointer)
+        if pointer != NULL :
+            dms = OBIWrapper.new_wrapper(DMS, pointer)
+        else :
+            dms = None
         return dms