def __init__(self, format="json", order="votes", proxy=None):
        if ['json', 'plaintext', 'rss'] not in format:
            raise FormatException('The format is invalid')

        self.format = format
        self.url = URL
        self.proxy = proxy

        if order == 'votes':
            self.order = 'sort-by-votes'
        elif order == 'date':
            self.order = ''
        else:
            raise OrderException('The order is invalid')
dataset/ETHPy150Open ncrocfer/clf/clf/api.py/Clf.__init__/swapped operands of `not in`