def all_subset_operators
      @entry.xpath('./*/cda:excerpt', HQMF2::Document::NAMESPACES).collect do |subset_operator|
        SubsetOperator.new(subset_operator)
      end
    end
def all_subset_operators
      @entry.xpath('./*/cda:excerpt', HQMF2::Document::NAMESPACES).collect do |subset_operator|
        SubsetOperator.new(subset_operator)
      end
    end
Extracts all subset operators contained in the entry xml