class Node:
def __init__(self, edges = set()):
self.edges = edges
def main():
foo = Node()
bar = Node()
quz = Node()
foo.edges.add(bar)
bar.edges.add(foo)
assert(foo is not bar) # assertion succeeds
assert(foo is not quz) # assertion succeeds
assert(bar is not quz) # assertion succeeds
assert(len(quz.edges) == 0) # assertion fails??
main()
spoiler
Mutable default values are shared across objects. The set in this case.
Ah sorry I meant a default argument which was a dict, thanks for the tip tho!