streamlining code and adding tests

[jGaboardi]

This PR:

• removes unneeded code chunks in utils.py
• adds corner case tests for functions in utils.py

[codecov[bot]]

Codecov Report

Merging #36 (a11072b) into main (e18a5a0) will increase coverage by 1.9%. The diff coverage is 81.2%.

@@           Coverage Diff           @@
##            main     #36     +/-   ##
=======================================
+ Coverage   78.8%   80.7%   +1.9%     
=======================================
  Files          5       5             
  Lines       1100    1075     -25     
  Branches     289     276     -13     
=======================================
+ Hits         867     868      +1     
+ Misses       165     144     -21     
+ Partials      68      63      -5     

Impacted Files	Coverage Δ
tigernet/utils.py	75.1% <78.6%> (+2.6%)	:arrow_up:
tigernet/tigernet.py	88.1% <100.0%> (ø)