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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 save(self, model, joining=None, touch=True):
 """ Save a new model and attach it to the parent model. :type model: eloquent.Model :type joining: dict :type touch: bool :rtype: eloquent.Model """

        if joining is None:
            joining = {}

        model.save({'touch': False})

        self.attach(model.get_key(), joining, touch)

        return model