Read the code carefully

import weakref
import gc


class Big:
    def __init__(self, label):
        self.label = label


obj = Big("A")
ref = weakref.ref(obj)
print(f"alive:{ref() is not None}")
print(f"label:{ref().label}")
del obj
gc.collect()
print(f"alive:{ref() is not None}")
print(f"deref:{ref()}")

What will the program print? Write here: