error msg is cv2.error: OpenCV(4.4.0) ../modules/dnn/src/layers/permute_layer.cpp:134: error: (-215:Assertion failed) (int)_numAxes == inputs[0].size() in function 'getMemoryShapes'

import torch.nn as nn
import torch


class BidirectionalLSTM(nn.Module):
    def __init__(self, input_size, hidden_size, output_size):
        super(BidirectionalLSTM, self).__init__()
        self.rnn = nn.LSTM(input_size, hidden_size, bidirectional=True, batch_first=True)
        self.linear = nn.Linear(hidden_size * 2, output_size)

    def forward(self, input):
        self.rnn.flatten_parameters()
        recurrent, _ = self.rnn(input)
        output = self.linear(recurrent)
        return output


class Model(nn.Module):
    def __init__(self):
        super(Model, self).__init__()
        self.SequenceModeling = nn.Sequential(
            BidirectionalLSTM(512, 512, 512),
            BidirectionalLSTM(512, 512, 512))

    def forward(self, input):
        contextual_feature = self.SequenceModeling(input)
        return contextual_feature


x = torch.rand(1, 65, 512).float().cpu()
model = Model()
model.eval()
torch.onnx.export(model, x, "ocr0811_1.onnx")


import cv2
net = cv2.dnn.readNetFromONNX('ocr0811_1.onnx')