@property
    def mtime(self):
        if callable(self._mtime):
            self._mtime = self._mtime(self.context)

        if self._mtime not in (NotSpecified, None) and type(self._mtime) is not int:
            self._mtime = int(self._mtime)

        return self._mtime
Mtime is set as a function to make it lazily computed via this property
dataset/ETHPy150Open realestate-com-au/harpoon/harpoon/option_spec/image_objs.py/Image.mtime