translate_document throws `Error occurred during document translation: no implicit conversion of nil into String (DeepL::Exceptions::DocumentTranslationError)` when source language is `nil` #8
translate_document states that param can be nil or string
# @param [String, nil] source_lang Source language to use for the translation. `nil` will cause
# automatic source langauge detection to be used. Must be
translate_document states that param can be nil or string
however when passing in a nil it errors
Using an empty string does work