@staticmethod
def load(file_name):
    with open(file_name, 'r') as fp:
        idx = ConversionIndex()
        obj = json.load(fp)
        idx.name = obj['name']
        idx.o2t = obj['o2t']
        idx.t2o = obj['t2o']
    return idx
@staticmethod
def load(file_name):
    with open(file_name, 'r') as fp:
        idx = ConversionIndex()
        obj = json.load(fp)
        idx.name = obj['name']
        idx.o2t = obj['o2t']
        idx.t2o = obj['t2o']
    return idx