'Remove things from the cached query if unchanged.
If the things have been changed since the specified timestamps, they
will not be removed.  This is useful for avoiding race conditions while
pruning.'

@classmethod
@tdb_cassandra.will_write
def remove_if_unchanged(cls, mutator, key, columns, timestamps):

    for col in columns:
        mutator.remove(cls._cf, key, columns=[col], timestamp=timestamps.get(col))
