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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 sync_entities_watching(instance):
 """ Syncs entities watching changes of a model instance. """

    for entity_model, entity_model_getter in entity_registry.entity_watching[instance.__class__]:
        model_objs = list(entity_model_getter(instance))
        if model_objs:
            sync_entities(*model_objs)