code: def DeregisterHelper(cls, resolver_helper):
      
      if resolver_helper.type_indicator not in cls._resolver_helpers:
        raise KeyError(
            'Resolver helper object not set for type indicator: {0:s}.'.format(
                resolver_helper.type_indicator))
  
      del cls._resolver_helpers[resolver_helper.type_indicator]
docs: Deregisters a path specification resolver helper.
  
      Args:
        resolver_helper (ResolverHelper): resolver helper.
  
      Raises:
        KeyError: if resolver helper object is not set for the corresponding
            type indicator.