def METHOD_NAME(self, input):
    """pre process"""
    input_arr = []
    input_lod = [0]
    start_lod = 0
    end_lod = 0
    for sub_item in input:
        end_lod = start_lod + len(sub_item)
        input_lod.append(end_lod)
        input_arr.extend(sub_item)
        start_lod = end_lod
    input_arr = np.array(input_arr)
    # print(input_arr.shape)
    # print([input_lod])
    return input_arr, [input_lod]