feat: optional static vars

[martibosch]

Prework

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[codecov]

Codecov Report

Attention: Patch coverage is 0% with 6 lines in your changes are missing coverage. Please review.

Project coverage is 23.23%. Comparing base (7481cb8) to head (eec8893).

Files	Patch %	Lines
tstore/tslong/pandas.py	0.00%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #23      +/-   ##
==========================================
- Coverage   23.37%   23.23%   -0.15%     
==========================================
  Files          37       37              
  Lines         663      667       +4     
==========================================
  Hits          155      155              
- Misses        508      512       +4     

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