def get_gold_answers(example):
    """helper function that retrieves all possible true answers from a squad2.0 example"""
    
    gold_answers = [answer["text"] for answer in example.answers if answer["text"]]

    # if gold_answers doesn't exist it's because this is a negative example - 
    # the only correct answer is an empty string
    if not gold_answers:
        gold_answers = [""]
        
    return gold_answers