Several City Chart
A week of temperature readings for several cities is displayed as overlapping, semi-transparent lines on a time-series chart, with a color legend identifying each city. The lines are ordered by their final temperature values using `d3.nest()` and a descending sort. The visualization uses D3 v5 with SVG rendering, including `d3.scaleTime`, `d3.scaleLinear`, `d3.scaleOrdinal`, `d3.line` with a basis curve, and axis components. Data is loaded from a CSV via `d3.csv` and formatted with `new Date` and numeric conversion.