code: def RegisterHelper(cls, resolver_helper):
      
      if resolver_helper.type_indicator in cls._resolver_helpers:
        raise KeyError((
            'Resolver helper object already set for type indicator: '
            '{0!s}.').format(resolver_helper.type_indicator))
  
      cls._resolver_helpers[resolver_helper.type_indicator] = resolver_helper
docs: Registers a path specification resolver helper.
  
      Args:
        resolver_helper (ResolverHelper): resolver helper.
  
      Raises:
        KeyError: if resolver helper object is already set for the corresponding
            type indicator.