Fix broken query generator for none param

[koxudaxi]

This PR fixes a broken query generator that can't bind None param.

Related issues

#49

[codecov]

Codecov Report

Merging #52 into master will not change coverage by %.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master       #52   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           12        12           
  Lines          539       540    +1     
  Branches        67        68    +1     
=========================================
+ Hits           539       540    +1     

Impacted Files	Coverage Δ
local_data_api/resources/resource.py	100.00% <100.00%> (ø)

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