Question: what is the name of the principal in matilda
[{'answer': 'Agatha Trunchbull', 'provenance': [{'wikipedia_id': '675935', 'title': 'Matilda (1996 film)', 'start_paragraph_id': 1, 'start_character': 448, 'end_paragraph_id': 1, 'end_character': 465, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]