status_line_fold_context.vim

augroup pythonFold
  autocmd!
  autocmd BufReadPre *.py setlocal foldmethod=indent
  autocmd CursorMovedI *.py call LightlineContext()
  autocmd CursorMoved *.py call LightlineContext()
augroup END


function! PinFold()
  " save current position
  let saveCursor = getcurpos()
  " Go to upper split, open all folds and go to the same line as bottom split
  normal! zR
  execute "normal! " . saveCursor[1] . "G"
  " Go to the beginning of the fold and put the line top of the upper split
  normal! [zkk
  normal! zt
  let contextline=getline('.')
  " Go back to bottom split and restore position
  call setpos('.', saveCursor)
  return contextline
endfunction


function! LightlineContext()
  return PinFold()
endfunction


Config for lightline:
      \ 'component_function': {
      \   'context': 'LightlineContext',
      \ },