You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: ndl_books_helper.rb
    path of file: ./repos/enju_leaf/app/helpers
    
    the code of the file until where you have to start completion: module NdlBooksHelper
  def link_to_import_from_ndl(iss_itemno)
    if iss_itemno.blank?
      t('enj
    
  def link_to_import_from_ndl(iss_itemno)
    if iss_itemno.blank?
      t('enju_ndl.not_available')
    else
      ndl_bib_id_record = NdlBibIdRecord.find_by(body: iss_itemno)
      if ndl_bib_id_record
        link_to t('enju_ndl.already_exists'), ndl_bib_id_record.manifestation
      else
        button_to t('enju_ndl.add'), ndl_books_path(book: {iss_itemno: iss_itemno}), method: :post, data: {disable_with: t('page.saving')}
      end