This source code was originally found on SourceForge and all credit goes to Phil Schwartz
Archived site linked to the code: arch:holidays.mailzilla.net
Research for a calendar project lead to http://www.fourmilab.ch/documents/calendar/ which is a very useful and well done project. There was a desire to find comparable Python code. When searching for existing Python libraries a number of good projects were found. However, Phil Schwartz's Python Date Utilities is a solid reproduction of the JavaScript code.
The code was written for Python2. It was trivial to make the minor edits to convert to Python3. (print statements -> print functions)
After using the library it became apparent that discrepancies existed. Somewhere there was a bug or a miscalculation.
It was initially observed when converting between Julian and Hebrew.
Combing through the code surfaced a rounding issue in hebrew_delay_1() which created incorrect dates.
The code is now re-shared on Github to hopefully disseminate Phil's code to a wider audience for years to come. This is Free Software: please use, modify, and share.