xml_utils: make rng_pivot return "starting" definition

Signed-off-by: Jan Pokorný <jpokorny@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/format.py b/format.py
index c36488e..990a1f8 100644
--- a/format.py
+++ b/format.py
@@ -499,7 +499,8 @@ class XML(SimpleFormat):
                     log.warning("Problem processing RNG file `{0}'".format(s))
                     continue
             if start is not None:
-                schema = rng_pivot(deepcopy(schema), start)
+                schema = deepcopy(schema)
+                rng_pivot(schema, start)
             try:
                 schema.assertValid(et)
             except etree.DocumentInvalid: