def __init__(self, input_layer, pool_size, stride=None): # pool_size is an INTEGER here!
        self.pool_size = pool_size
        self.stride = stride if stride is not None else pool_size
        self.input_layer = input_layer
        self.params = []
        self.bias_params = []
        self.mb_size = self.input_layer.mb_size

        self.pool_op = MaxPool(ds=self.pool_size, stride=self.stride)
pool_size is an INTEGER, not a tuple. We can only do square pooling windows.
dataset/ETHPy150Open benanne/kaggle-galaxies/cc_layers.py/CudaConvnetPooling2DLayer.__init__