This example demonstrates how to use the D3 collection API to inspect and iterate over JavaScript objects. It defines a simple month object with four key-value pairs and then logs the results of `d3.keys`, `d3.values`, and `d3.entries` to the browser console. Using D3 v4 within a plain HTML page, the code shows how these utility functions extract property names, values, and key-value pairs as arrays, respectively, with no data visualization or chart rendered.