Feature: type and value checks for transformers + minor refactoring

[rushilg99]

No description provided.

[codecov]

Codecov Report

Merging #1262 (1f9e6ca) into develop (243146f) will decrease coverage by 0.56%.
Report is 1 commits behind head on develop.
The diff coverage is 7.84%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1262      +/-   ##
===========================================
- Coverage    76.18%   75.62%   -0.56%     
===========================================
  Files           61       61              
  Lines         5404     5445      +41     
===========================================
+ Hits          4117     4118       +1     
- Misses        1287     1327      +40     

Files	Coverage Δ
macrosynergy/learning/__init__.py	100.00% <ø> (ø)
macrosynergy/learning/metrics.py	19.48% <0.00%> (ø)
macrosynergy/learning/prediction_tools.py	14.17% <0.00%> (ø)
macrosynergy/learning/panel_time_series_split.py	60.75% <0.00%> (+0.75%)	⬆️
macrosynergy/learning/transformers.py	14.18% <8.51%> (-4.86%)	⬇️