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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 prefetch_translations(instances, **kwargs):
 """ Prefetches translations for the given instances. Can be useful for a list of instances. """

    from .mixins import ModelMixin

    if not isinstance(instances, collections.Iterable):
        instances = [instances]

    populate_missing = kwargs.get("populate_missing", True)
    grouped_translations = utils.get_grouped_translations(instances, **kwargs)

    # In the case of no translations objects
    if not grouped_translations and populate_missing:
        for instance in instances:
            instance.populate_missing_translations()

    for instance in instances:
        if (
            issubclass(instance.__class__, ModelMixin)
            and instance.pk in grouped_translations
        ):
            for translation in grouped_translations[instance.pk]:
                instance._linguist.set_cache(instance=instance, translation=translation)
            if populate_missing:
                instance.populate_missing_translations()