in archive/preprocess/clospan.py [0:0]
def consumeSeq(self, old):
if not old.parents:
raise RuntimeError("Trying to merge the root or a sequence without parents.")
if self.parents:
self.parents = self.parents.union(old.parents)
if old in self.parents:
self.parents.remove(old)
else:
self.parents = old.parents
for p in old.parents:
p.children.remove(old)
p.children.add(self)