Vim command to convert variable into spec let(:var)

https://github.com/garybernhardt/dotfiles/blob/master/.vimrc

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" PROMOTE VARIABLE TO RSPEC LET
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function! PromoteToLet()
  :normal! dd
  " :exec '?^\s*it\>'
  :normal! P
  :.s/\(\w\+\) = \(.*\)$/let(:\1) { \2 }/
  :normal ==
endfunction
:command! PromoteToLet :call PromoteToLet()
:map <leader>p :PromoteToLet<cr>