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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 bind_df_model(model_fit, arima_results):
 """Set model degrees of freedom. Older versions of statsmodels don't handle this issue. Sets the model degrees of freedom in place if not already present. Parameters model_fit : ARMA, ARIMA or SARIMAX The fitted model. arima_results : ModelResultsWrapper The results wrapper. """

    if not hasattr(arima_results, 'df_model'):
        df_model = model_fit.k_exog + model_fit.k_trend + \
            model_fit.k_ar + model_fit.k_ma + \
            model_fit.k_seasonal_ar + model_fit.k_seasonal_ma
        setattr(arima_results, 'df_model', df_model)