Explain why previous value is dropped from window  [ci skip]
Explain why previous value is dropped from window  [ci skip]

jakirkham/rank_filter,nanshe-org/rank_filter,nanshe-org/rank_filter,nanshe-org/rank_filter,jakirkham/rank_filter,DudLab/rank_filter,DudLab/rank_filter,jakirkham/rank_filter,DudLab/rank_filter