cached_property.py

class cached_property(property):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.cache_name = f'_{self.fget.__name__}'
        
    def __get__(self, obj, type):
        if not hasattr(obj, self.cache_name):
            value = super().__get__(obj, type)
            setattr(obj, self.cache_name, value)
        return getattr(obj, self.cache_name)