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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 _clean_cleaned_data(self):
 """ delete auxilary fields not belonging to node model """

        reference_node_id = 0

        if '_ref_node_id' in self.cleaned_data:
            reference_node_id = self.cleaned_data['_ref_node_id']
            del self.cleaned_data['_ref_node_id']

        position_type = self.cleaned_data['_position']
        del self.cleaned_data['_position']

        return position_type, reference_node_id