`pyparser` vs `pyparsing`

I see you have both `pyparser` and `pyparsing` in your `requirements.txt`. However, only `pyparser` is in the `setup.py` as a dependency. Moreover, I only see a use of the `pyparsing` library in the code.

It seems to me that *only* `pyparsing` should be in the `requirements.txt` *and* in `setup.py` as a dependency. What do you all think?

For reference:
- `pyparser`: Code: https://keep.imfreedom.org/grim/pyparser, PyPI: https://pypi.org/project/pyparser/
- `pyparsing`: Code: https://github.com/pyparsing/pyparsing, PyPI: https://pypi.org/project/pyparsing/

Start by comparing requirements.txt and setup.py, then inspect the code references to pyparsing. Confirm which package is actually required, update both dependency declarations consistently, and verify that installation and the existing test suite still work.

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