def myComplexOperation(signal):
    import numpy as np
    a = np.array(arg1)
    return a*2

        Runtime.PythonDLL = @"C:\Python38\python38.dll";
        var pathToVirtualEnv = Path.GetFullPath(Path.Combine(Directory.GetCurrentDirectory(), @"..\..\..\venv"));
        Console.WriteLine(pathToVirtualEnv);

        string additional = $"{pathToVirtualEnv};{pathToVirtualEnv}\\Lib\\site-packages;{pathToVirtualEnv}\\Lib";
        PythonEngine.PythonPath = PythonEngine.PythonPath + ";" + additional;
        Console.WriteLine(PythonEngine.PythonPath);

        PythonEngine.Initialize();
        PythonEngine.BeginAllowThreads();

        List<object> objParams = new List<object>();
       objParams.Add(1+2j);  // Complex
       objParams.Add(2+3j); // Complex
      
       PyList myPyLst = new PyList();
       for (int nPos = 0; nPos < objParams.Count; nPos++)
       {
           myPyLst.Append(objParams[nPos]);
       }
      
      PyObject[] pyParams = new PyObject[2];
      pyParams[i] = myPyLst

      var locals = new PyDict();
      PythonEngine.Exec(cmd, null, locals);
      var execFunc = locals.GetItem("myComplexOperation");

    using (Py.GIL())
    {
        PyObject result;
        result = execFunc.Invoke(pyParams);
       // here is the problem:
       // The code works when parameter is String (PyString), Integer (PyInt or PyFloat), PyList (strings, numerics)
       // but not working when using a PyList with Complex number for Numpy operations.
      // The return is empty     
    }