An integer or tuple/list of 3 integers:
(pool_depth, pool_height, pool_width)
specifying the size of the pooling window.
Can be a single integer to specify the same value for
all spatial dimensions.
strides
An integer or tuple/list of 3 integers,
specifying the strides of the pooling operation.
Can be a single integer to specify the same value for
all spatial dimensions.
padding
A string. The padding method, either 'valid' or 'same'.
Case-insensitive.
data_format
A string. The ordering of the dimensions in the inputs.
channels_last (default) and channels_first are supported.
channels_last corresponds to inputs with shape
(batch, depth, height, width, channels) while channels_first
corresponds to inputs with shape
(batch, channels, depth, height, width).