class CachedRange:
    _PRECOMPUTE_RANGES = ['30d', '90d', '6m', '1y', '2y', 'all']
    # I despise magic strings but this is about as good as I can get without enum support
    def __init__(self, _range: str):
        if _range not in CachedRange._PRECOMPUTE_RANGES:
            raise ValueError(f'Invalid range: {_range}')
        self._range = _range

    @property
    def range(self):
        return self._range

    def __str__(self):
        return self._range