fix onnx export bug

hnluo

2023-08-29 72b6c7735e44fff12c4a3d401deb98c59f16ab0f

 funasr/models/specaug/abs_specaug.py

New file
@@ -0,0 +1,16 @@
from typing import Optional
from typing import Tuple

import torch


class AbsSpecAug(torch.nn.Module):
    """Abstract class for the augmentation of spectrogram
    The process-flow:
    Frontend  -> SpecAug -> Normalization -> Encoder -> Decoder
    """

    def forward(
        self, x: torch.Tensor, x_lengths: torch.Tensor = None
    ) -> Tuple[torch.Tensor, Optional[torch.Tensor]]:
        raise NotImplementedError