The process of apprenticeship described in this book will make laugh anyone who actually went through a real apprenticeship from a Peruvian curandero, and actually, can even be dangerous for those who would start practicing shupar or other techniques as described in the book, without the proper training and protection.
First of all, in that part of the Amazon, apprenticeship goes through master plant dietas, done in isolation in the jungle for weeks or even months. The author did none of that, and strangely, it wasn't even offered by the maestro.
Second, she describes that she started singing some icaros in English in her first sessions... It doesn't happen like this. Icaros are either received from the maestro, or from the plants, and will not be given in the first ceremonies. One has to first manage to control the trance, and to clean oneself, before starting to receive anything. In any book about Ayahuasca, you will never read that indigenous people start screaming random icaros on their first ceremonies, it takes time to be able to sing icaros properly.
And third, about shupar, sucking bad energy on Ayahuasca. She describes she starts doing that at some point, very shortly in her training. It never happens like this. This is a dangerous operation to do, and curanderos do it only when they have dieted enough to have a strong mariri that will prevent the bad energy to go in their body. It is very unlikely that a shaman will tell somebody with no dieta and no mariri to suck someone's energy.
There are still many things in this book that doesn't sound true at all, 100% fake story from my point of view, and even wondering if the author has really been to Peruvian Amazon.