def clean_merge h1, h2
  dup_keys = h2.keys.each_with_object([]) do |key, arr|
    arr << key if h1.keys.include? key
  end

  if dup_keys.count > 0
    h2.clone.map do |k, v|
      if dup_keys.include? k
        h2['dup_' + k.to_s] = h2.delete(k)
      end
    end
  end

  h1.merge(h2)
end