Removing slide doesn't remove slides from [Content_Types].xml

[jamieshield]

Removing slide doesn't remove the slide's relationships from [Content_Types].xml.
That is, calling removeSlide to remove slide 2 does delete the following from [Content_Types].xml.

From my naive diagnosis, calling removeSlide calls the factory removeSlide.
removeSlide(slide) {
this.powerPointFactory.removeSlide(slide.name);

The factory removeSlide calls removeContentType(partName)
factories/index.js:
removeSlide(slideName) { ...
this.contentTypeFactory.removeContentType(/ppt/slides/${slideName}.xml);

However, removeContentType is defined with two parameters partName and contentType.
So the contentType never matches and the slides' relationship in ContentType.xml is not removed.

Adding a default parameter was a (hack) solution for me.
node-pptx/lib/factories/content-types.js:
removeContentType(partName, contentType = "application/vnd.openxmlformats-officedocument.presentationml.slide+xml")

Time poor newbie reporting an issue - just trying to help. Apologies in advance for any inappropriateness in this issue report.