fix task.py with no dest_sample_rate task; fix bug in train and infer

mengzhe.cmz

2023-04-12 1ad439f96b8cdbca98ee95b886d692dfa20e85ce

 funasr/train/abs_model.py

@@ -1,8 +1,6 @@
from abc import ABC
from abc import abstractmethod
from typing import Tuple

import torch

from typing import Dict
from typing import Optional