def default_header_deduplicators
      @default_header_deduplicators ||= {
        deduplicate: proc do |columns|
          Helpers.key_count_to_deduplicated_array(columns)
        end,
        raise: proc do |columns|
          duplicates = Helpers.duplicated_items(columns)
          if duplicates.any?
            message = "all columns must be unique, duplicates are: #{duplicates}"
            raise(Errors::DuplicateHeaderColumnError, message)
          end
          columns
        end,
        none: proc { |columns| columns },
      }.freeze
    end
def default_header_deduplicators
      @default_header_deduplicators ||= {
        deduplicate: proc do |columns|
          Helpers.key_count_to_deduplicated_array(columns)
        end,
        raise: proc do |columns|
          duplicates = Helpers.duplicated_items(columns)
          if duplicates.any?
            message = "all columns must be unique, duplicates are: #{duplicates}"
            raise(Errors::DuplicateHeaderColumnError, message)
          end
          columns
        end,
        none: proc { |columns| columns },
      }.freeze
    end
Default header deduplicate strategies
 @return [Hash] the default header deduplicatation strategies