code: async def decrypt(self, ciphertext: bytes, sender: str = None) -> (bytes, str):
          
  
          LOGGER.debug('BaseAnchor.decrypt >>> ciphertext: %s, sender: %s', ciphertext, sender)
  
          if not self.wallet.handle:
              LOGGER.debug('BaseAnchor.decrypt <!< Wallet %s is closed', self.name)
              raise WalletState('Wallet {} is closed'.format(self.name))
  
          from_verkey = None
          if sender:
              from_verkey = await self._verkey_for(sender)
          rv = await self.wallet.decrypt(
              ciphertext,
              True if from_verkey else None,
              to_verkey=None,
              from_verkey=from_verkey)
  
          LOGGER.debug('BaseAnchor.decrypt <<< %s', rv)
          return rv
docs: Decrypt ciphertext and optionally authenticate sender.
  
          Raise BadKey if authentication operation reveals sender key distinct from current
          verification key of owner of input DID.  Raise WalletState if wallet is closed.
  
          :param ciphertext: ciphertext, as bytes
          :param sender: DID or verification key of sender, None for anonymously encrypted ciphertext
          :return: decrypted bytes and sender verification key (None for anonymous decryption)