def METHOD_NAME(self, arg):
    if arg == "tct":
        encoder = TctColBertQueryEncoder("castorini/tct_colbert-msmarco")
        index = "msmarco-passage-tct_colbert-hnsw"
    elif arg == "ance":
        encoder = AnceQueryEncoder("castorini/ance-msmarco-passage")
        index = "msmarco-passage-ance-bf"
    else:
        print(
            f'Model "{arg}" is invalid. Model should be one of [tct, ance].')
        return
    self.dsearcher = FaissSearcher.from_prebuilt_index(
        index,
        encoder
    )
    self.hsearcher = HybridSearcher(self.dsearcher, self.ssearcher)
    print(f'setting model = {arg}')