♻️ improve QOL with mypy

[jvdd]

Closes #118

[codspeed-hq]

CodSpeed Performance Report

Merging #120 will degrade performances by 19.39%

_{Comparing mypy (d1e29a4) with main (e7890be)}

Summary

⚡ 2 improvements
❌ 1 regressions
✅ 378 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	mypy	Change
⚡	test_single_series_feature_collection_multiple_descriptors[1]	23,494.6 ms	441.7 ms	×53
⚡	test_single_series_feature_collection_multiple_descriptors[2]	1,254.1 ms	458.3 ms	×2.7
❌	test_single_series_feature_collection_multiple_descriptors[4]	383.8 ms	476.1 ms	-19.39%

[jvdd]

LGTM