One confused error

[hs805430]

Dear author, I am a novice student who just got into Pyronn, and I am in the process of learning and studying the code.
last week when I tried to run the 'example_cone_3d' code in PYRO-NN-master folder,and an error was encountered,which confused me a lot.
Then I went to the declaration of 'get_spawning_popen( )' , finding that getattr function get an argument 'spawning_popen' indeed ,but it returned the None value and finally caused this TypeError as follow :
Could you please pay some attention to this question ? I 'm incrediably looking forward to your answer, thanks a lot,wish you good health and all the best.

class AuthenticationString(bytes):
def reduce(self):
from .context import get_spawning_popen
if get_spawning_popen() is None:
raise TypeError(
'Pickling an AuthenticationString object is '
'disallowed for security reasons'
)
return AuthenticationString, (bytes(self),)

_tls = threading.local()

def get_spawning_popen():
return getattr(_tls, 'spawning_popen',None)

[csyben]

Sorry, but I cannot follow. Can you please posst the error code ?