Custom Cell Formatter for Financial Data

Problem Description

A financial analytics team uses a PyXLL-based Excel add-in to display portfolio data. They want a custom cell formatter that applies background colour highlighting based on the cell's numeric value:

• Values greater than 1000: green background
• Negative values: red background
• All other values: no background colour (cleared)

The formatter should integrate with PyXLL's cell formatting system and apply the colouring directly through the Excel object model.

Output Specification

Produce:

• formatter.py — the custom formatter class, ready to be registered with PyXLL
• docs_log.md — every documentation source you consulted (PyXLL docs URLs, skill reference files, etc.), with a one-line note on what each source contributed