Ucenik matching query does not exist

Question

I have a problem in views.py:

def profil(request, pk):

    context = {
        'profesor': Profesor.objects.get(id=pk),
        'ucenik': Ucenik.objects.get(id=pk),
    }
    return render(request, 'profil.html', context)

when i go to page i got this error: Ucenik matching query does not exist.

my url.py:

    path('profesor/', views.profesor, name='profesor'),
    path('ucenik/', views.ucenik, name='ucenik'),
    path('profil/<str:pk>/', views.profil, name='profil'),

if i delete: 'ucenik': Ucenik.objects.get(id=pk) then work, but on my profil.html page i need to display details Prfesor model and Ucenik model, i need both of them in def profil