code: async def sign(self, message: bytes) -> bytes:
          
  
          LOGGER.debug('BaseAnchor.sign >>> message: %s', message)
  
          if not self.wallet.handle:
              LOGGER.debug('BaseAnchor.sign <!< Wallet %s is closed', self.name)
              raise WalletState('Wallet {} is closed'.format(self.name))
  
          rv = await self.wallet.sign(message)
  
          LOGGER.debug('BaseAnchor.sign <<< %s', rv)
          return rv
docs: Sign message; return signature. Raise WalletState if wallet is closed.
  
          :param message: Content to sign, as bytes
          :return: signature, as bytes