FIX: DM.to_sparse_dataframe returns a copy.
FIX: DM.to_sparse_dataframe returns a copy.

ericdill/datamuxer,tacaswell/dataportal,ericdill/databroker,danielballan/dataportal,NSLS-II/dataportal,NSLS-II/dataportal,NSLS-II/datamuxer,tacaswell/dataportal,danielballan/dataportal,danielballan/datamuxer,danielballan/datamuxer,ericdill/datamuxer,ericdill/databroker