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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 get_natural_key_fields(cls):
 """ Determine actual natural key field list, incorporating the natural keys of related objects as needed. """

        natural_key = []
        for name, rel_to in cls.get_natural_key_info():
            if not rel_to:
                natural_key.append(name)
            else:
                nested_key = rel_to.get_natural_key_fields()
                natural_key.extend([
                    name + '__' + nname
                    for nname in nested_key
                ])
        return natural_key