tenseal编写CKKS时报错

Question

我在用tenseal写CKKS加密代码，但是出现了错误：

ctx = context(
    scheme=SCHEME_TYPE.CKKS,
    poly_modulus_degree=4096,
    coeff_mod_bit_sizes=[60, 40, 40, 60],
    encryption_type=ENCRYPTION_TYPE.ASYMMETRIC,
    n_threads=16
)
ctx.global_scale = 2 ** 40
secret_key = ctx.secret_key()

但是报错了

Traceback (most recent call last):
  File "D:\PyCharm Community Edition 2021.3.2\batchcrypt-master\111\practice_model.py", line 47, in <module>
    n_threads=16
  File "D:\anaconda3\envs\py37\lib\site-packages\tenseal\__init__.py", line 65, in context
    return Context(*args, **kwargs)
  File "D:\anaconda3\envs\py37\lib\site-packages\tenseal\enc_context.py", line 144, in __init__
    n_threads,
ValueError: encryption parameters are not set correctly

Process finished with exit code 1

请问这是为什么