code: def secret_key_bytes(self):
          ''' Return the secret_key, converted to bytes and cached.
  
          '''
          if not hasattr(self, '_secret_key_bytes'):
              key = self.secret_key()
              if key is None:
                  self._secret_key_bytes = None
              else:
                  self._secret_key_bytes = codecs.encode(key, "utf-8")
          return self._secret_key_bytef secret_key_bytes(self):
          ''' Return the secret_key, converted to bytes and cached.
  
          '''
          if not hasattr(self, '_secret_key_bytes'):
              key = self.secret_key()
              if key is None:
                  self._secret_key_bytes = None
              else:
                  self._secret_key_bytes = codecs.encode(key, "utf-8")
          return self._secret_key_bytes
docs: Return the secret_key, converted to bytes and cached.