def prt():
print(list(Thing.things.keys()))
class Thing:
things = {}
def __init__(self):
Thing.things[id(self)] = self
def __del__(self):
print('__del__')
del(Thing.things[id(self)])
def main():
prt()
t1 = Thing()
prt()
t2 = Thing()
prt()
t3 = Thing()
prt()
t4 = None
prt()
main()
prt()
[]
[140300136976832]
[140300136976832, 140300136335632]
[140300136976832, 140300136335632, 140300136334528]
[140300136976832, 140300136335632, 140300136334528]
[140300136976832, 140300136335632, 140300136334528]
__del__
__del__
__del__