bugfix: fix the previous fix

bfps/DNS.py

@@ -847,6 +847,7 @@ class DNS(_code):
                          min(dst_shape[1], src_file[src_dset_name].shape[1]),
                          min(dst_shape[2], src_file[src_dset_name].shape[2]),
                          3)
+            src_shape = src_file[src_dset_name].shape
             dst_file.create_dataset(
                     dst_dset_name,
                     shape = dst_shape,