 (str, optional, defaults to "UNetMidBlock1D") — Block type for middle of UNet.   out_block_type (str, optional, defaults to None) — Optional output processing block of UNet.   act_fn (str, optional, defaults to None) — Optional activation function in UNet blocks.   norm_num_groups (int, optional, defaults to 8) — The number of groups for normalization.   layers_per_block (int, optional, defaults to 1) — The number of layers per block.   downsa