code: def is_secret_registered(
              self,
              secrethash: SecretHash,
              block_identifier: BlockSpecification,
      ) -> bool:
          
          if not self.client.can_query_state_for_block(block_identifier):
              raise NoStateForBlockIdentifier()
  
          block = self.get_secret_registration_block_by_secrethash(
              secrethash=secrethash,
              block_identifier=block_identifier,
          )
          return block is not None
docs: True if the secret for `secrethash` is registered at `block_identifier`.
  
          Throws NoStateForBlockIdentifier if the given block_identifier
          is older than the pruning limit