forecasting values for each category using Prophet in python

I am very new to doing time series in Python and Prophet. I have a dataset with the variables article code, date and quantity sold. I am trying to forecast the quantity sold for each article for each month using Prophet in python.

I tried using for loop for performing the forecast for each article, But I am not sure how to display the article type in output(forecast) data and also write it to a file directly from the "for loop".

df2 = df2.rename(columns={'Date of the document': 'ds','Quantity sold': 'y'})
for article in df2['Article bar code']:

    # set the uncertainty interval to 95% (the Prophet default is 80%)
    my_model = Prophet(weekly_seasonality= True, daily_seasonality=True,seasonality_prior_scale=1.0)
    my_model.fit(df2)
    future_dates = my_model.make_future_dataframe(periods=6, freq='MS')
    forecast = my_model.predict(future_dates)
return forecast

I want the output like below, and want this to be written to an output file directly from the "for loop".

Thanks in Advance.

Separate your dataframe by articletype and then try storing all your predicted values in a dictionary

def get_prediction(df):
    prediction = {}
    df = df.rename(columns={'Date of the document': 'ds','Quantity sold': 'y', 'Article bar code': 'article'})
    list_articles = df2.article.unique()

    for article in list_articles:
        article_df = df2.loc[df2['article'] == article]
        # set the uncertainty interval to 95% (the Prophet default is 80%)
        my_model = Prophet(weekly_seasonality= True, daily_seasonality=True,seasonality_prior_scale=1.0)
        my_model.fit(article_df)
        future_dates = my_model.make_future_dataframe(periods=6, freq='MS')
        forecast = my_model.predict(future_dates)
        prediction[article] = forecast
    return prediction

now the prediction will have forecasts for each type of article.