Attribute error

[sastry3009]

Thanks for your work, but I have a question about it.
in case of redd dataset there are two meters in site meter so only one meter of site meter is loaded to dis aggregate as like this
train_mains = train_elec.mains().all_meters()[0]

but i use synd dataset for this i have only one meter so i modified this as
train_mains = train_elec.mains()
with this code i got the Attribute error. as shown below

could you please suggest me the solution

Thanking you