seher karakuzu

started mypy implementation for tiled: Note lots of mypy errors!

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beginning of mypy implementation in tiled. It is not ready to merge.

refactor `__init__.py` in `utils` directory

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Separated `__init__.py` into `utils.py`, `helper_functions.py` and `Msg.py` imported everthing in `__init__.py` closes #1677

Add arrow adapter

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### Checklist - [ ] Add a Changelog entry - [ ] Add the ticket number which this PR closes to the comment section

preliminary start of sql adapter. to be continued ... ### Checklist - [ ] Add a Changelog entry - [ ] Add the ticket number which this PR closes to...

Calling `.items()` and `__getitem__` methods from CVS and Arrow adapters result in error when the table includes strings. The primary reason can be `dask` not recognizing the string type. More...