in archive/preprocess/clospan.py [0:0]
def __init__(self, s, Ids, p = None):
self.s = s
self.Ids = Ids
self.children = None
if p:
self.parents = set([p])
if p.children:
p.children.add(self)
else:
p.children = set([self])
else:
self.parents = None