def header_deduplicator=(strategy)
      if header_deduplicator_registry.type?(strategy)
        @header_deduplicator = header_deduplicator_registry[strategy]
      elsif strategy.respond_to?(:call)
        @header_deduplicator = strategy
      else
        message = "unknown deduplication strategy: '#{strategy}'"
        raise(Errors::UnknownDeduplicationStrategyError, message)
      end
    end
def header_deduplicator=(strategy)
      if header_deduplicator_registry.type?(strategy)
        @header_deduplicator = header_deduplicator_registry[strategy]
      elsif strategy.respond_to?(:call)
        @header_deduplicator = strategy
      else
        message = "unknown deduplication strategy: '#{strategy}'"
        raise(Errors::UnknownDeduplicationStrategyError, message)
      end
    end
Set the deduplication header strategy
 @param [Symbol, #call]
   symbol with known strategy identifier or method that responds
   to #call(colums, key_count)
 @return [#call] the header deduplication strategy
 @raise [UnknownDeduplicationStrategyError]