D3: SVG Arc Circle

Forked script adapts from D3.js v4 to v3

• d3.arc() v4 object replaces v3’s d3.svg.arc().
• .attrs({}) method contains multiple attribute tuples. Replacing v3’s .attr({}).

Forked v4 script above. Original v3 script below.

D3.js 3.5.17 seems to have an existence similar to Python 2.7.14. Maintained to avoid alienating v3 users.