Adding support to provide custom labels to sequence classification

[lalitpagaria]

To complete #25

[lalitpagaria]

@cdpierse Can you please review PR

[cdpierse]

@lalitpagaria thank you very much for this PR, it's a great addition to the classification explainer and one I've wanted to add for a while, so I really appreciate it.

I've left one request for a minor change to be made to the docstring but besides that the rest looks good. The implementation is really clean.

I'm also currently using the black formatter for the entire repo so once you have the next change done could you run black . from the project's root.

Thanks also for writing the additional tests, it's a big help in getting things merged quicker.

[lalitpagaria]

Thanks for the review. Updated PR with suggested changes ie doc string and black formatting.

[cdpierse]

Amazing work. This is a fantastic PR thanks @lalitpagaria. I'm merging this into dev now and this will be part of the next release 0.4.0 which should hopefully be within the next 2 weeks.

[lalitpagaria]

Thanks @cdpierse for this amazing tool
I want to integrate use it with https://github.com/lalitpagaria/obsei
So user able to interpret prediction made by AI models like zero shot, sentiment or NER etc.