timestamp,target_value,item_id
2014-12-31 20:00:00,NaN,client_370
2014-12-31 21:00:00,NaN,client_370
2014-12-31 22:00:00,NaN,client_370
2014-12-31 23:00:00,NaN,client_370
2015-01-01 00:00:00,NaN,client_370
2014-12-31 20:00:00,0.14,client_371
2014-12-31 21:00:00,0.14,client_371
2014-12-31 22:00:00,0.15,client_371
2014-12-31 23:00:00,0.18,client_371
2015-01-01 00:00:00,0.18,client_371
2014-12-31 20:00:00,NaN,client_372
2014-12-31 21:00:00,NaN,client_372
2014-12-31 22:00:00,NaN,client_372
2014-12-31 23:00:00,NaN,client_372
2015-01-01 00:00:00,NaN,client_372
2014-12-31 20:00:00,24.0,client_373
2014-12-31 21:00:00,34.0,client_373
2014-12-31 22:00:00,35.0,client_373
2014-12-31 23:00:00,24.0,client_373
2015-01-01 00:00:00,36.0,client_373