docs: def FindLocalHREF(self, href, elt, headers=1):
          '''Find a local HREF in the data elements.
          '''
          if href[0] != '#':
              raise EvaluateException(
                  'Absolute HREF ("%s") not implemented' % href,
                  self.Backtrace(elt))
          frag = href[1:]
          # Already found?
          e = self.id_cache.get(frag)
          if e: return e
          # Do a breadth-first search, in the data first.  Most likely
          # to find multi-ref targets shallow in the data area.
          list = self.data_elements[:] + [self.body_root]
          if headers: list.extend(self.header_elements)
          while list:
              e = list.pop()
              if e.nodeType == _Node.ELEMENT_NODE:
                  nodeid = _find_id(e)
                  if nodeid:
                      self.id_cache[nodeid] = e
                      if nodeid == frag: return e
              list += _children(e)
          raise EvaluateException('''Can't find node for HREF "%s"''' % href,
                  self.Backtrace(elt))