Instruct: Classify a review as either positive or negative.
Query: Understanding of the charaters

What is the most atonishing thing of the art of Maria Callas is the deep understanding of everything that she sung during her life and is with all her dramatic resources that she learns all the singers in her masterclasses with the 'many colours and intonations for all voices and operas and for me is this that had transformed her in the major lyric artist among all others wonderful singers that we know.