HistoQC: 'float' object is not subscriptable"

Ran without modifications, running in the python:3-stretch docker container.

2019-05-06 22:08:10,702 - INFO - no display found. Using non-interactive Agg backend
2019-05-06 22:08:11,899 - WARNING - Configuration file not set (--config), using default: /var/www/HistoQC/config.ini
2019-05-06 22:08:11,902 - INFO - Pipeline will use these steps:
2019-05-06 22:08:11,903 - INFO - 		BasicModule	getBasicStats
2019-05-06 22:08:12,267 - INFO - 		ClassificationModule	byExampleWithFeatures:coverslip_edge
2019-05-06 22:08:12,402 - INFO - 		LightDarkModule	getIntensityThresholdPercent:tissue
2019-05-06 22:08:12,404 - INFO - 		LightDarkModule	getIntensityThresholdPercent:darktissue
2019-05-06 22:08:12,404 - INFO - 		BubbleRegionByRegion	detectSmoothness
2019-05-06 22:08:12,406 - INFO - 		MorphologyModule	removeFatlikeTissue
2019-05-06 22:08:12,408 - INFO - 		MorphologyModule	fillSmallHoles
2019-05-06 22:08:12,408 - INFO - 		MorphologyModule	removeSmallObjects
2019-05-06 22:08:12,409 - INFO - 		BlurDetectionModule	identifyBlurryRegions
2019-05-06 22:08:12,410 - INFO - 		BasicModule	finalProcessingSpur
2019-05-06 22:08:12,411 - INFO - 		BasicModule	finalProcessingArea
2019-05-06 22:08:12,411 - INFO - 		HistogramModule	compareToTemplates
2019-05-06 22:08:12,413 - INFO - 		HistogramModule	getHistogram
2019-05-06 22:08:12,414 - INFO - 		BrightContrastModule	getContrast
2019-05-06 22:08:12,415 - INFO - 		BrightContrastModule	getBrightnessGray
2019-05-06 22:08:12,415 - INFO - 		BrightContrastModule	getBrightnessByChannelinColorSpace:RGB
2019-05-06 22:08:12,416 - INFO - 		BrightContrastModule	getBrightnessByChannelinColorSpace:YUV
2019-05-06 22:08:12,417 - INFO - 		DeconvolutionModule	seperateStains
2019-05-06 22:08:12,418 - INFO - 		SaveModule	saveFinalMask
2019-05-06 22:08:12,419 - INFO - 		SaveModule	saveThumbnails
2019-05-06 22:08:12,420 - INFO - 		BasicModule	finalComputations
2019-05-06 22:08:12,420 - INFO - ----------
2019-05-06 22:08:12,421 - INFO - Number of files detected by pattern:	1
2019-05-06 22:08:12,422 - INFO - -----Working on:	/images/apply.svs		1 of 1
2019-05-06 22:08:12,458 - INFO - apply.svs - 	getMag
2019-05-06 22:08:15,450 - INFO - apply.svs - 	getBasicStats
2019-05-06 22:08:15,450 - INFO - apply.svs - 	ClassificationModule.byExample:	coverslip_edge
2019-05-06 22:08:15,453 - INFO - apply.svs - Training model ClassificationModule.byExample:coverslip_edge
2019-05-06 22:08:15,489 - ERROR - /images/apply.svs - 	 - Error analyzing file (skipping): 	 <class 'TypeError'> Inappropriate argument type. ("'float' object is not subscriptable", '/images/apply.svs', '<code object byExampleWithFeatures at 0x7fdde4d93e40, file "/var/www/HistoQC/ClassificationModule.py", line 143>')
2019-05-06 22:08:15,496 - INFO - ------------Done---------

2019-05-06 22:08:15,496 - INFO - These images failed (available also in error.log), warnings are listed in warnings column in output:
2019-05-06 22:08:15,496 - INFO - /images/apply.svs	<class 'TypeError'> Inappropriate argument type. ("'float' object is not subscriptable", '/images/apply.svs', '<code object byExampleWithFeatures at 0x7fdde4d93e40, file "/var/www/HistoQC/ClassificationModule.py", line 143>')
2019-05-06 22:08:15,497 - INFO - Symlink to output directory created