code: def _init_special(self):
          
          self._special_del = {}
          self._special_del['SCANNERS'] = _del_SCANNERS
  
          self._special_set = {}
          for key in reserved_construction_var_names:
              self._special_set[key] = _set_reserved
          for key in future_reserved_construction_var_names:
              self._special_set[key] = _set_future_reserved
          self._special_set['BUILDERS'] = _set_BUILDERS
          self._special_set['SCANNERS'] = _set_SCANNERS
  
          # Freeze the keys of self._special_set in a list for use by
          # methods that need to check.  (Empirically, list scanning has
          # gotten better than dict.has_key() in Python 2.5.)
          self._special_set_keys = list(self._special_set.keys())
docs: Initial the dispatch tables for special handling of
          special construction variables.