Dataset from UCI contains the  electricity consumption (in kWh) of 320 customers every 15 minutes from 2011 to 2014.     For  some customers, their electricity consumption data was recorded starting from a different time,  and the data before the first record was marked as 0.     As training model requires a starting point for the time series, and different customers  have different starting times, some features remain 0 before a certain time point.     Using all  the data for training would inevitably have a negative impact.     Therefore, the data  from 2011 is removed  and set the starti