value.py 文件源码

def __init__(self, generator=undefined,  initial_value=undefined,
                 equal=None, always_recompute=False, *, tracker=None):
        super().__init__(tracker=tracker)
        self._equal = equal or operator.eq
        self._descriptor_initialized = False
        self._single_value_initialized = False
        if callable(generator):
            # suppose it's used as a method decorator
            self._generator = generator
            self._value = initial_value
        elif generator is not undefined:
            self._generator = None
            self._value = generator
        else:
            self._generator = None
            self._value = initial_value
        self._comp = None
        self._always_recompute = always_recompute