code: def dec(self, byts):
          '''
          Decode an envelope dict and decrypt the given bytes.
  
          Args:
              byts (bytes): Bytes to decrypt.
  
          Returns:
              bytes: Decrypted message.
          '''
          envl = s_msgpack.un(byts)
          iv = envl.get('iv', b'')
          asscd = envl.get('asscd', b'')
          data = envl.get('data', b'')
  
          decryptor = AESGCM(self.ekey)
  
          try:
              data = decryptor.decrypt(iv, data, asscd)
          except Exception:
              logger.exception('Error decrypting data')
              return None
          return datf dec(self, byts):
          '''
          Decode an envelope dict and decrypt the given bytes.
  
          Args:
              byts (bytes): Bytes to decrypt.
  
          Returns:
              bytes: Decrypted message.
          '''
          envl = s_msgpack.un(byts)
          iv = envl.get('iv', b'')
          asscd = envl.get('asscd', b'')
          data = envl.get('data', b'')
  
          decryptor = AESGCM(self.ekey)
  
          try:
              data = decryptor.decrypt(iv, data, asscd)
          except Exception:
              logger.exception('Error decrypting data')
              return None
          return data
docs: Decode an envelope dict and decrypt the given bytes.
  
          Args:
              byts (bytes): Bytes to decrypt.
  
          Returns:
              bytes: Decrypted message.