def forward(self, x):
        """
        Returns output tensor after passing input `x` to the neural network
        block.

        Parameters
        ----------
            x : tensor
                input to the NN block.

        Returns
        -------
            tensor
                output of the NN block.
        """


        # Average pooling with kernel size 2 (2 x 2).
        x = F.avg_pool2d(x, 2)
        # Convolution + Leaky ReLU
        x = F.leaky_relu(self.conv1(x), negative_slope = 0.1)
        # Convolution + Leaky ReLU
        x = F.leaky_relu(self.conv2(x), negative_slope = 0.1)
        return x

        Returns output tensor after passing input `x` to the neural network
        block.

        Parameters
        ----------
            x : tensor
                input to the NN block.

        Returns
        -------
            tensor
                output of the NN block.
        
model.py