seasonality
statsmodels tsa
statsmodels.tsa.seasonal.seasonal_decompose — statsmodels
https://www.statsmodels.org/dev/generated/statsmodels.tsa.seasonal.seasonal_decompose.html
Paid Tutorial
Seasonality, trend and noise in time series data | Python
https://campus.datacamp.com/courses/visualizing-time-series-data-in-python/seasonality-trend-and-noise?ex=6
Prophet