Assemble: A Small Sales Dashboard

The problem, from first principles

A dashboard is several charts answering several questions about the same data, on one figure, with one consistent look. The pieces are all things you have built: a time series, a ranked bar chart, a histogram. The work is in the joining: aggregating the data for each panel (the line wants monthly totals, the bars want per-region totals, the histogram wants the raw order values), labelling every axis so each panel stands alone, and putting a title over the whole figure.

This question builds a three-panel sales dashboard from one table of orders, and because every panel is built from matplotlib objects you can check each one against the aggregation it should show.

From theory to code

Implement sales_dashboard(df). The signature and docstring are already in the editor.

Constraints

• df has the columns date (datetime), region (text) and amount (number), with at least one row.
• Return fig, a figure with exactly three Axes in one row (plt.subplots(1, 3)), in this order: revenue by month, revenue by region, order amounts.
• Panel 1 is a line of the total amount per calendar month, in chronological order, with the title "Revenue by month", x label "Month" and y label "Revenue".
• Panel 2 is a bar chart of the total amount per region, largest total first (ties by region name ascending), bars centred at 0..n-1 with the region names as tick labels, title "Revenue by region", x label "Region", y label "Revenue".
• Panel 3 is a histogram of the raw amount values with 5 bins, title "Order amounts", x label "Amount", y label "Orders".
• The figure has the overall title (suptitle) "Sales dashboard". Do not call plt.show().

Hints