Enhancement: Remove `statistics.py` module and clean up `const.py`

[CM000n]

Just a tiny little improvement I've just stumbled across. We should use == instead of is to compare str types in stastics.py.

..::edit::.. Silly question, but is the stastics.py module still used anywhere? 😆 Looks like this is a remnant and could be deleted completely?

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (1a17a62) 80.11% compared to head (456b224) 82.86%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #317 +/- ## ========================================== + Coverage 80.11% 82.86% +2.75% ========================================== Files 32 31 -1 Lines 1514 1436 -78 ========================================== - Hits 1213 1190 -23 + Misses 301 246 -55 ``` | [Flag](https://app.codecov.io/gh/DurgNomis-drol/mytoyota/pull/317/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Simon+Hansen) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/DurgNomis-drol/mytoyota/pull/317/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Simon+Hansen) | `82.86% <ø> (+2.75%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Simon+Hansen#carryforward-flags-in-the-pull-request-comment) to find out more.

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[CM000n]

Can you please take a look at it and approve it, if the changes okay for you @GitOldGrumpy?