Add a new optional initialization argument output to AccumulationTable

[AinaMerch]

Add a new optional initialization argument output to AccumulationTable. This argument is either be None (default), or a string representing a filepath. If a filepath is provided, the AccumulationTable writes its table to that file rather than to standard output

Motivation and Context

Adds additional functionality as described above.

Your Changes

Modified accumulation_table.py to implement functionality and added tests in test_accumulation_table.py

Description:

Type of change (select all that apply):

• New feature (non-breaking change which adds functionality)
• Documentation update (change that modifies or updates documentation only)

Testing

Wrote tests in the test file.
Manually tested on different functions in different situations.

Questions and Comments (if applicable)

Checklist

• I have performed a self-review of my own code.
• I have verified that the CI tests have passed.
• I have reviewed the test coverage changes reported on Coveralls.
• I have added tests for my changes.
• I have updated the CHANGELOG.md file.

[coveralls]

Pull Request Test Coverage Report for Build 7145297637

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 94.604%

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Totals
Change from base Build 7123781450:	0.0%
Covered Lines:	3419
Relevant Lines:	3614

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💛 - Coveralls