text: 
  from index_element import IndexElement
  
  class ExtendedIndexElement(IndexElement):
      
      def __init__(self, index, entry, section_title, specification=None):
          self.section_title = section_title
          self.extended_entry = entry
          self.specification = specification
          IndexElement.__init__(self,section_title + "/" + entry + "/" + unicode(specification),index)
      
      def to_array(self):
          return [self.entry] + sorted(list(self.index))
  
      def __add__(self,other):
          if isinstance(other,ExtendedIndexElement):
              return ExtendedIndexElement(self.index | other.index,self.extended_entry,self.section_title,self.specification)
          else:
             return IndexElement.__add__(self,other)
                  