def step_ARIMA(resid, p_max, d_max, q_max):
    from statsmodels.tsa.arima_model import ARIMAResults    
    from statsmodels.tsa.arima_model import ARIMA
    best_BIC = 9999999999999999.0
    for p in range(p_max + 1):
        for d in range(d_max + 1):
            for q in range(q_max + 1):
                if(p > 0 or q > 0):
                    try:
                        order = (p, d, q)
                        BIC, order, model = model_ARIMA_2(resid, order)
                        if(BIC < best_BIC):
                            best_model = model
                            best_BIC = BIC
                            best_order = order
                    except: 
                        pass        
    return(best_BIC, best_order, best_model)