code: def calculateSignature(privateSigningKey, message):
          
          if privateSigningKey.getType() == Curve.DJB_TYPE:
              rand = os.urandom(64)
              res = _curve.calculateSignature(rand, privateSigningKey.getPrivateKey(), message)
              return res
          else:
              raise InvalidKeyException("Unknown type: %s" % privateSigningKey.getType())
docs: :type privateSigningKey: ECPrivateKey
          :type  message: bytearray