IronPython: no module named 'nltk'

Question

i use ironPython last version 3.4.1 in Nuget (https://www.nuget.org/packages/IronPython/3.4.1#readme-body-tab)

so, i got simple .py file with that code (let's name it test.py):

import nltk
def calculate_bleu(reference, candidate):
return nltk.translate.bleu_score.sentence_bleu(reference, candidate)

and I have another .cs file which use IronPython package and executes this code (testME.cs) PS this is tests use NUnit 3.1:

[TestFixture]
public class Test
{
[TestCase]
public void TestIt()
    {

ScriptEngine engine = Python.CreateEngine();
            string dir = Path.GetDirectoryName(@"C:\Users\my_user\repository\test.py");
            ICollection<string> paths = engine.GetSearchPaths();
        if (!String.IsNullOrWhiteSpace(dir))
        {
            paths.Add(dir);
        }
        else
        {
            paths.Add(Environment.CurrentDirectory);
        }

        paths.Add(@"c:\Users\my_user\AppData\Roaming\Python\Python311\site-packages\nltk\translate\bleu_score.py");
        paths.Add(@"C:\Program Files\Python311");
        paths.Add(@"C:\Program Files\Python311\Lib");
        paths.Add(@"C:\Program Files\Python311\site-packages");
        paths.Add(@"C:\Program Files\Python311\site-packages\nltk");

        engine.SetSearchPaths(paths);

        ScriptScope scope = engine.CreateScope();
        engine.ExecuteFile(@"C:\Users\my_user\repository\test.py", scope);
        dynamic testFunction = scope.GetVariable("calculate_bleu");

        var result = testFunction("this is a dog", "this is a cat");
    }

}

so, when I run this code I got an error about 'NLTK' module like: Message: 

IronPython.Runtime.Exceptions.ImportException : No module named 'nltk'

Stack Trace:  LightExceptions.ThrowException(LightException lightEx) LightExceptions.CheckAndThrow(Object value) FuncCallInstruction`2.Run(InterpretedFrame frame) Interpreter.Run(InterpretedFrame frame) LightLambda.Run2[T0,T1,TRet](T0 arg0, T1 arg1) PythonScriptCode.RunWorker(CodeContext ctx) PythonScriptCode.Run(Scope scope) RuntimeScriptCode.InvokeTarget(Scope scope) RuntimeScriptCode.Run(Scope scope) SourceUnit.Execute(Scope scope, ErrorSink errorSink) SourceUnit.Execute(Scope scope) ScriptSource.Execute(ScriptScope scope) ScriptEngine.ExecuteFile(String path, ScriptScope scope)

If i run this "@"C:\Users\my_user\repository\test.py"" thorugh console -> there is successfull result ( i tried execute 'print' -> it prints the result); library nltk is installed globally for me; I set up all python paths as SetSearchPaths (i googled it can be the solution) nltk package version is 3.5 (i googled there are problems with less version of it)

are there any of the other possible solutions which could be helpful for me? i'd be happy for any info; thank you