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: product_nature_categories_controller.rb
    path of file: ./repos/ekylibre/app/controllers/backend
    
    the code of the file until where you have to start completion: # == License
# Ekylibre - Simple agricultural ERP
# Copyright (C) 2013 Brice Texier, David Joulin
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for mo
    
    def edit
      @product_nature_category = find_and_check
      @form_url = backend_product_nature_category_path(@product_nature_category)
      @key = 'product_nature_category'
      # infos concerning mass changing account on category
      fy = FinancialYear.opened.order(:started_on)
      started_at = fy.first.started_on.to_time
      stopped_at = fy.last.stopped_on.to_time
      sales_or_purchases_or_assets_count = 0
      sales_or_purchases_or_assets_count += PurchaseItem.of_product_nature_category(@product_nature_category).between(started_at, stopped_at).count
      sales_or_purchases_or_assets_count += SaleItem.of_product_nature_category(@product_nature_category).between(started_at, stopped_at).count
      sales_or_purchases_or_assets_count += FixedAsset.of_product_nature_category(@product_nature_category).start_between(started_at.to_date, stopped_at.to_date).count
      notify_warning_now(:there_are_x_existing_items_on_category_to_update_if_you_change_account, count: sales_or_purchases_or_assets_count) if sales_or_purchases_or_assets_count > 0
      t3e(@product_nature_category.attributes)
    end