I tried it with multi indexes and found two different bugs which needs to be managed separately. This method will work with multi indexes only when a single multi-index is provided

1. I think there is a bug in #pos method of Daru::MultiIndex when multiple multi-indexes are provided. access_row_tuples_by_index will work in this case when the issue with pos method will be resolved.
   
   

2. #pos method is working fine in the below case but #access_row_tuples_by_indexs gives error as it uses index for creating new rows but the provided index is not actually the valid index. It is used to get the positions.
   

Ping @zverok , @v0dro Please look into the PR as soon as possible.

Thanks!

Note: in dataframe.rb, it is possible to use instead:

def access_row_tuples_by_indexs *indexes
  get_sub_dataframe(indexes, by_position: false).map_rows(&:to_a)
end

It is about 10 times slower that the current reverted code but, among the two bugs found by @Prakriti-nith , it is not affected by the second one (ie I have:

df.access_row_tuples_by_indexs [:a, :one]
=> [[11, 1], [12, 2]]

)

Thanks @paisible-wanderer for informing us. @Prakriti-nith , please use similar thing for dataframe having multi index and test it for different cases.