Operation: Do not set field when no result is available

[dbaston]

References #138

[codecov]

Codecov Report

Attention: Patch coverage is 80.95238% with 4 lines in your changes missing coverage. Please review.

Project coverage is 90.91%. Comparing base (9af0c0b) to head (c3cc593).
Report is 1 commits behind head on master.

Files	Patch %	Lines
python/src/exactextract/writer.py	78.94%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #140      +/-   ##
==========================================
- Coverage   90.98%   90.91%   -0.07%     
==========================================
  Files          85       85              
  Lines        6312     6309       -3     
  Branches      622      621       -1     
==========================================
- Hits         5743     5736       -7     
- Misses        537      541       +4     
  Partials       32       32              

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