#NEWLINE# @ property #NEWLINE# def serialization_id( self ) : #NEWLINE# #INDENT# "\n        serialization_id is used to keep items locally sorted and unique\n        (eg. used redis sorted sets' score or cassandra column names)\n\n        serialization_id is also used to select random activities from the feed\n        (eg. remove activities from feeds must be fast operation)\n        for this reason the serialization_id should be unique and not change over time\n\n        eg:\n        activity.serialization_id = 1373266755000000000042008\n        1373266755000 activity creation time as epoch with millisecond resolution\n        0000000000042 activity left padded object_id (10 digits)\n        008 left padded activity verb id (3 digits)\n\n        :returns: int --the serialization id\n        " #NEWLINE# milliseconds = str ( ( int ( datetime_to_epoch ( milliseconds . updated_at ) ) * 1000 ) ) #NEWLINE# return milliseconds