towardsdatascience.com › flask-and-chart-jsDashboard Tutorial (I): Flask and Chart.js | Towards Data Science Jun 10, 2020 · Plot4: Doughnut Chart (Semi-Circle) Bar Line Chart. First, we need to prepare the dataset for the Bar Line Chart. This chart mainly places focus on the cumulative_cases, cumulative_recovered, cumulative_deaths, and active_cases_change of COVID in Alberta from January to June.