def build(self, builder, base_url=None, **kwargs):
return builder(base_url=base_url).build(self, **kwargs)
- def assign_ids(self):
+ def assign_ids(self, existing=None):
# Find all existing IDs.
- existing = set()
+ existing = existing or set()
que = [self.tree.getroot()]
while que:
item = que.pop(0)