self.avg_pool = nn.AdaptiveAvgPool2d((1, 1))

This code snippet creates an instance of the nn.AdaptiveAvgPool2d module with a target output size of (1, 1).

The AdaptiveAvgPool2d module is used for global average pooling, which is a technique commonly used in convolutional neural networks for image classification. It takes as input a tensor of shape (batch_size, channels, height, width), and computes the average value of each channel across all spatial dimensions (height and width) to produce a tensor of shape (batch_size, channels, 1, 1).

By setting the output size to (1, 1), the module ensures that the resulting tensor has a fixed size regardless of the input size, which can be useful for downstream layers that require a fixed input size.