def extract_negation
      negation = (attr_val('./*/@actionNegationInd').to_s.downcase == 'true')
      negation_code_list_id = nil
      if negation
        res = @entry.at_xpath('./*/cda:outboundRelationship/*/cda:code[@code="410666004"]/../cda:value/@valueSet',
                              HQMF2::Document::NAMESPACES)
        negation_code_list_id = res.value if res
      end
      [negation, negation_code_list_id]
    end
def extract_negation
      negation = (attr_val('./*/@actionNegationInd').to_s.downcase == 'true')
      negation_code_list_id = nil
      if negation
        res = @entry.at_xpath('./*/cda:outboundRelationship/*/cda:code[@code="410666004"]/../cda:value/@valueSet',
                              HQMF2::Document::NAMESPACES)
        negation_code_list_id = res.value if res
      end
      [negation, negation_code_list_id]
    end
Extract the negation (and the negation_code_list_id if appropriate)