tensorflow_federated no attribute 'Popen' error

[yizirui]

I'm new here and setting up the environment for CIFER and MNIST baselines on Colab. However, I got the following error for all baselines: Exception ignored in: <function local_cpp_executor_factory.<locals>.ServiceManager.__del__ at 0x7fae95ec1b80> Traceback (most recent call last): File "/usr/local/lib/python3.9/dist-packages/tensorflow_federated/python/core/impl/executor_stacks/executor_factory.py", line 150, in __del__ AttributeError: 'NoneType' object has no attribute 'Popen'. Some are with NotImplementedError: numpy() is only available when eager execution is enabled.. I was trying to find information about it but was not able to fix it. Could anyone kindly let me know what's wrong with it? Thanks.