def checkpoint(self, cp):
"Create a checkpoint from arbitrary object 'cp'"
checkpoint = Checkpoint(self, cp, author = "anonymous")
valid = checkpoint.test()
print "Tested checkpoint %r and got result %r" % (cp, valid)
if valid:
if self.owner:
checkpoint.quorum.sign(self.identity)
self.owner.attempt_checkpoint(self, checkpoint)
else:
checkpoint.enact()
