Fix and normalize loader args

[timkpaine]

fixes #80

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.76%. Comparing base (b7bc651) to head (1b1c06c).
⚠️ Report is 23 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #94      +/-   ##
==========================================
+ Coverage   87.32%   87.76%   +0.43%     
==========================================
  Files          14       14              
  Lines        1065     1103      +38     
==========================================
+ Hits          930      968      +38     
  Misses        135      135              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.