Group a list of objects (django model) by a foreign model

gistfile1.py

def group_by_foreign_model():
    """
    Example of the model:

    class MyModel(Model):
       foreign = models.ForeignKey(MyForeignModel)
    """

    result = MyModel.objects.all()

    # key is the ID foreign model
    values = sorted(result, key=lambda x:x.foreign.id)

    # key is the foreign model
    return [(x,list(y)) for x,y  in itertools.groupby(values, key=lambda x:x.foreign)]