pythonnet on Sagemaker cannot import clr - mono

Question

I cannot import clr from SageMaker with this error.
What kind of tweaks make this successful ?
From Sagemaker console :
source activate python3
conda install pythonnet
This seems to finely install pythonnet without error.
In python code :
import clr
This produce this error :
Traceback (most recent call last):
File "test_clr.py", line 1, in <module>
import clr
ImportError: System.TypeInitializationException: The type initializer for 'Sys' threw an exception. ---> System.DllNotFoundException: /home/ec2-user/anaconda3/envs/python3/lib/../lib/libmono-native.so assembly:<unknown assembly> type:<unknown type> member:(null)
at (wrapper managed-to-native) Interop+Sys.LChflagsCanSetHiddenFlag()
at Interop+Sys..cctor () [0x00000] in <aa5dff9b31c64fce86559bbbf6cd364f>:0
--- End of inner exception stack trace ---
at Interop.GetRandomBytes (System.Byte* buffer, System.Int32 length) [0x00000] in <aa5dff9b31c64fce86559bbbf6cd364f>:0
at System.Guid.FastNewGuidArray () [0x00020] in <aa5dff9b31c64fce86559bbbf6cd364f>:0
at System.Reflection.Emit.ModuleBuilder..ctor (System.Reflection.Emit.AssemblyBuilder assb, System.String name, System.String fullyqname, System.Boolean emitSymbolInfo, System.Boolean transient) [0x00035] in <aa5dff9b31c64fce86559bbbf6cd364f>:0
at System.Reflection.Emit.AssemblyBuilder.DefineDynamicModule (System.String name, System.String fileName, System.Boolean emitSymbolInfo, System.Boolean transient) [0x0005b] in <aa5dff9b31c64fce86559bbbf6cd364f>:0
at System.Reflection.Emit.AssemblyBuilder.DefineDynamicModule (System.String name) [0x00000] in <aa5dff9b31c64fce86559bbbf6cd364f>:0
at Python.Runtime.CodeGenerator..ctor () [0x0002b] in <0e10ac2b10a44c1baa160aa337220b6a>:0
at Python.Runtime.DelegateManager..ctor () [0x00061] in <0e10ac2b10a44c1baa160aa337220b6a>:0
at Python.Runtime.PythonEngine.Initialize (System.Collections.Generic.IEnumerable`1[T] args, System.Boolean setSysArgv, System.Boolean initSigs) [0x0000a] in <0e10ac2b10a44c1baa160aa337220b6a>:0
at Python.Runtime.PythonEngine.Initialize (System.Boolean setSysArgv, System.Boolean initSigs) [0x00005] in <0e10ac2b10a44c1baa160aa337220b6a>:0
at Python.Runtime.PythonEngine.InitExt () [0x00000] in <0e10ac2b10a44c1baa160aa337220b6a>:0
Environment :
Amazon Linux AMI release 2018.03
Mono JIT compiler version 6.12.0.90 (tarball Fri Mar 5 04:37:13 UTC 2021)
Python 3.6.13
conda 4.8.4
pythonnet 2.4.0
Similar symptoms :
System.DllNotFoundException when trying to import clr, despite referenced assembly existing #1034 : I confirmed libmono-native.so library there in the right directory.