'Retrieve the items in a set of cached queries.
For each cached query, this returns the thing tuples and the column
timestamps for them.  The latter is useful for conditional removal
during pruning.'

@classmethod
def get(cls, keys):

    rows = cls._cf.multiget(keys, include_timestamp=True, column_count=tdb_cassandra.max_column_count)
    res = {}
    for (row, columns) in rows.iteritems():
        data = []
        timestamps = []
        for (key, (value, timestamp)) in columns.iteritems():
            value = json.loads(value)
            data.append(((key,) + tuple(value)))
            timestamps.append((key, timestamp))
        res[row] = (data, dict(timestamps))
    return res
