Improve the code coverage

[klaasnicolaas]

Improve the code in models for code coverage

[codecov]

Codecov Report

Merging #21 (1cca2d4) into master (fbcbb87) will increase coverage by 1.17%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #21      +/-   ##
==========================================
+ Coverage   86.45%   87.62%   +1.17%     
==========================================
  Files           4        4              
  Lines          96       97       +1     
  Branches       12       12              
==========================================
+ Hits           83       85       +2     
  Misses          9        9              
+ Partials        4        3       -1     

Impacted Files	Coverage Δ
omnikinverter/models.py	100.00% <100.00%> (+2.56%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update fbcbb87...1cca2d4. Read the comment docs.