Fix hint binding

[illusional]

Second second of fixes related to #36

[codecov]

Codecov Report

Merging #39 into master will decrease coverage by 1.82%.
The diff coverage is 47.05%.

@@            Coverage Diff             @@
##           master      #39      +/-   ##
==========================================
- Coverage   81.93%   80.11%   -1.83%     
==========================================
  Files          10       10              
  Lines         681      709      +28     
==========================================
+ Hits          558      568      +10     
- Misses        123      141      +18

Impacted Files	Coverage Δ
cwlgen/workflow.py	81.94% <30.76%> (-11.28%)	⬇️
cwlgen/commandlinetool.py	82.07% <57.14%> (-6.94%)	⬇️

---

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 13eb4f3...4bc451b. Read the comment docs.