change camelback to underscore

[ashtul]

similar to #53

[codecov]

Codecov Report

Merging #54 into master will decrease coverage by 1.33%.
The diff coverage is 98.48%.

@@             Coverage Diff             @@
##            master      #54      +/-   ##
===========================================
- Coverage   100.00%   98.66%   -1.34%     
===========================================
  Files            2        2              
  Lines          322      374      +52     
===========================================
+ Hits           322      369      +47     
- Misses           0        5       +5     

Impacted Files	Coverage Δ
redistimeseries/client.py	99.47% <96.96%> (-0.53%)	⬇️
test_commands.py	97.83% <100.00%> (-2.17%)	⬇️

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