@property
def uri(self):
    if (self._uri is None):
        self._uri = f'http://iiif.io/api/image/3/level{int(self)}.json'
    return self._uri
@property
def uri(self):
    if (self._uri is None):
        self._uri = f'http://iiif.io/api/image/3/level{int(self)}.json'
    return self._uri