To define well-defined promo strategy, I once need to analysis data in terms of impacts of promos. In that case, since data is based on time series, I once referred to use time series decomposition. After I decomposed observed data into trend, seasonal, and residual components, We exposed the impact of promos clearly to make a decision which promo is better in each country.
In addition, I used Random Forest Regression in this forecasting problem to boost our decision.
LIBRARIES USED- statsmodels, pandas, sklearn, seaborn METHOD: Random Forest Regressor