Protect against double subscription

[danielballan]

Closes #76

[codecov-io]

Codecov Report

Merging #77 into master will increase coverage by 4.29%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master      #77      +/-   ##
==========================================
+ Coverage   48.05%   52.34%   +4.29%     
==========================================
  Files          13       13              
  Lines         720      724       +4     
==========================================
+ Hits          346      379      +33     
+ Misses        374      345      -29

Impacted Files	Coverage Δ
nslsii/__init__.py	6.76% <0%> (-0.21%)	⬇️
nslsii/_version.py	44.4% <0%> (+1.8%)	⬆️
nslsii/tests/temperature_controllers_test.py	100% <0%> (+33.33%)	⬆️
nslsii/temperature_controllers.py	91.83% <0%> (+36.73%)	⬆️

---

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 1545ae6...f2b597c. Read the comment docs.

[mrakitin]

Thanks for the quick turnaround!

[tacaswell]

I think it would be better to stash this in the namespace passed into configure_base, not in the nslsii module.

[danielballan]

True. That approach is better because it allows for the possibility of running multiple times as long as the namespaces are separate (good for tests) and it works even if the user does reload(nslsii).

[mrakitin]

Looks good to me as long as the syntax error is resolved.