Debug the preprocessing of integer matrix input

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Codecov Report

Attention: Patch coverage is 60.00000% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 23.04%. Comparing base (08d8c97) to head (53c9f0e).

Files	Patch %	Lines
dynamo/preprocessing/gene_selection.py	0.00%	4 Missing :warning:

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #664 +/- ## ======================================= Coverage 23.03% 23.04% ======================================= Files 161 161 Lines 27761 27765 +4 ======================================= + Hits 6396 6398 +2 - Misses 21365 21367 +2 ```

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