能不能在这段代码的基础上，将GRU换成BiGRU，并在BiGRU的后面加入多头注意力机制

当然可以，以下是将LSTNet中的GRU替换为BiGRU，并在其后添加多头注意力机制的代码示例： ```python import torch import torch.nn as nn import torch.nn.functional as F class LSTNet(nn.Module): def __init__(self, input_size, hidden_size, skip_size, ar_window, cnn_kernel, cnn_layers, output_fun='sigmoid', num_heads=8): super(LSTNet, self).__init__() self.input_size = input_size self.hidden_size = hidden_size self.skip_size = skip_size self.ar_window = ar_window self.cnn_kernel = cnn_kernel self.cnn_layers = cnn_layers self.output_fun = output_fun self.num_heads = num_heads # BiGRU layer self.rnn = nn.GRU(input_size, hidden_size, bidirectional=True) # Multi-Head Attention layer self.attention = nn.MultiheadAttention(hidden_size*2, num_heads=num_heads) # CNN layers layers =