When posting the following book, there is an error telling that the corriculum is None. However, the corriculum is not null. [Matthew Walker PhD - Why We Sleep_ Unlocking the Power of Sleep and Dreams-Scribner (2017).pdf](https://github.com/CogitoNTNU/TutorAI/files/15162150/Matthew.Walker.PhD.-.Why.We.Sleep_.Unlocking.the.Power.of.Sleep.and.Dreams-Scribner.2017.pdf)
When posting the following book, there is an error telling that the corriculum is None. However, the corriculum is not null.
Matthew Walker PhD - Why We Sleep_ Unlocking the Power of Sleep and Dreams-Scribner (2017).pdf