Improve BasicTemplate type hints

[MarcSkovMadsen]

Fixes issues like below

[MarcSkovMadsen]

I don't know how you got type hints in using | @philippjfr ? These will fail when running on Python < 3.10 I believe.

[codecov]

Codecov Report

Merging #3562 (28262f4) into master (003dbb6) will decrease coverage by 0.03%.
The diff coverage is 100.00%.

❗ Current head 28262f4 differs from pull request most recent head 130d933. Consider uploading reports for the commit 130d933 to get more accurate results

@@            Coverage Diff             @@
##           master    #3562      +/-   ##
==========================================
- Coverage   82.82%   82.79%   -0.04%     
==========================================
  Files         199      199              
  Lines       27518    27471      -47     
==========================================
- Hits        22792    22744      -48     
- Misses       4726     4727       +1     

Impacted Files	Coverage Δ
panel/template/base.py	77.36% <100.00%> (+0.04%)	⬆️
panel/widgets/input.py	94.18% <0.00%> (-2.47%)	⬇️
panel/io/resources.py	87.05% <0.00%> (-0.06%)	⬇️
panel/auth.py	41.45% <0.00%> (ø)
panel/param.py	86.51% <0.00%> (ø)
panel/config.py	59.88% <0.00%> (ø)
panel/io/rest.py	31.63% <0.00%> (ø)
panel/io/save.py	63.63% <0.00%> (ø)
panel/__init__.py	100.00% <0.00%> (ø)
panel/__main__.py	100.00% <0.00%> (ø)
... and 104 more

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[philippjfr]

The union operator is compatible with from __future__ import annotations in older versions of python. You just can't express type aliases that way.

[MarcSkovMadsen]

Thanks. Does it mean I should refactor this one to annotate using Path | str | List[Path| str] instead of Union[Path, str, List[Union[Path, str]] and add from __future__ import annotations @philippjfr ?

[MarcSkovMadsen]

Thanks. Does it mean I should refactor this one to annotate using Path | str | List[Path| str] instead of Union[Path, str, List[Union[Path, str]] and add from __future__ import annotations @philippjfr ?

I can see from #3560 (comment) that it does. I will update.

[philippjfr]

Perfect, thanks!

[philippjfr]

Finished typing template/base.py in this PR.