Error when using GridSearchCV n_jobs=-1 #2449

Private Sub btnInitPython_Click(sender As Object, e As EventArgs) Handles btnInitPython.Click
    Dim aPythonPath(5) As String
    aPythonPath(0) = "C:\Users\NICE531\anaconda3\envs\pyflow_env\python39.dll"
    aPythonPath(1) = "C:\Users\NICE531\anaconda3\envs\pyflow_env"
    aPythonPath(2) = "C:\Users\NICE531\anaconda3\envs\pyflow_env"
    aPythonPath(3) = "N"
    aPythonPath(4) = ""

    Dim sConntionScript As String = PyEngine.Init(aPythonPath(0), aPythonPath(1), aPythonPath(2), aPythonPath(3), aPythonPath(4))

    MsgBox(sConntionScript)
End Sub

Private Sub btnExecScript_Click(sender As Object, e As EventArgs) Handles btnExecScript.Click
    Dim sScript As String = "

return best_model

return rfr_model, pred_data

Public Shared Function Init(ByVal aPythonDLL As String, ByVal aPythonHome As String, ByVal aPythonInstallPath As String, ByVal aisPythnVenv As String, ByVal aPythonPath As String) As String
    Dim sConntionVersion As String = String.Empty

    Try
        Runtime.PythonDLL = aPythonDLL

        If aisPythnVenv <> "N" Then
            Environment.SetEnvironmentVariable("VIRTUAL_ENV", aPythonInstallPath, EnvironmentVariableTarget.Process)
        Else
            Environment.SetEnvironmentVariable("PYTHONHOME", aPythonHome, EnvironmentVariableTarget.Process)
        End If

        Environment.SetEnvironmentVariable("PYTHONPATH", aPythonPath, EnvironmentVariableTarget.Process)

        PythonEngine.Initialize()
        PythonEngine.BeginAllowThreads()

        Using Py.GIL()
            m_Scope = Py.CreateScope
        End Using

        sConntionVersion = "Python " & PythonEngine.Version
    Catch ex As Exception
        Throw New Exception(ex.Message)
    End Try
    Return sConntionVersion
End Function

Public Shared Function PyExec(ByVal aScript As String) As String
    Try
        Using Py.GIL()
            m_Scope.Exec(aScript)
        End Using

        Return "finish"
    Catch ex As Exception
        Return ex.Message
    End Try
End Function