Revert "Merge pull request #10 from huggingface/fix-target-perplexity" (#14)
* Revert "Merge pull request #10 from huggingface/fix-target-perplexity"
This reverts commit 192574282c697204cb83676a66ceb1d03c26745c, reversing
changes made to 0cf83ceb0f104d724cac604b8edb5075694ff93f.
* fix