code: def addRelation(self, link):
          '''Appends Relation
          
          '''
          if isinstance(link, Relation):
              self.internalLinks.append(link)
          else:
              raise TypeError(
                  'link Type should be InternalLink, not %s' % type(link)f addRelation(self, link):
          '''Appends Relation
          
          '''
          if isinstance(link, Relation):
              self.internalLinks.append(link)
          else:
              raise TypeError(
                  'link Type should be InternalLink, not %s' % type(link))
docs: Appends Relation