Các lớp con feed-forward

class FeedForwardSubLayer(nn.Module):
    def __init__(self, d_model, d_ff):
        super().__init__()
        # Define the layers and activation
        self.fc1 = ____
        self.fc2 = ____
        self.relu = ____

    def forward(self, x):
        # Pass the input through the layers and activation
        return self.____(self.____(self.____(x)))
    
# Instantiate the FeedForwardSubLayer and apply it to x
feed_forward = ____
output = ____
print(f"Input shape: {x.shape}")
print(f"Output shape: {output.shape}")