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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def instance_from_url(url, user=None):
 """ Restore instance from URL """

    # XXX: This circular dependency will be removed then filter_queryset_for_user
    # will be moved to model manager method
    from waldur_core.structure.managers import filter_queryset_for_user

    url = clear_url(url)
    match = resolve(url)
    model = get_model_from_resolve_match(match)
    queryset = model.objects.all()
    if user is not None:
        queryset = filter_queryset_for_user(model.objects.all(), user)
    return queryset.get(**match.kwargs)