def evaluating_forward(self, batch_data):
        """
        Forward pass for evaluating the model.
        Abstract method to be implemented.

        Parameters
        ----------
        batch_data : tuple
            The batch data for evaluating the model.

        Returns
        -------
        output : numpy array
            The output of the model.
        """
        # An example implementation:
        # x = batch_data
        # x_gpu = x.to(self.device)
        # # x, y = batch_data
        # # x_gpu = x.to(self.device)
        # # y = y.to(self.device)
        # output = self.model(x_gpu)
        # return pairwise_distances_no_broadcast(x.numpy(),
        #                                        output.cpu().numpy())
        pass

        Forward pass for evaluating the model.
        Abstract method to be implemented.

        Parameters
        ----------
        batch_data : tuple
            The batch data for evaluating the model.

        Returns
        -------
        output : numpy array
            The output of the model.
        
pyod/models/base_dl.py