code: def __init__(self, input_spec: FeatureMapsSpecification):
      if input_spec is None:
          raise ValueError("input_spec must be specified")
      super().__init__()
      self.input_spec = input_spec
  
imports: import dataclasses
  from abc import abstractmethod
  from typing import Protocol, Tuple, List, Union, Mapping, Callable
  import numpy
  import torch.jit
  from torch import nn, Tensor
  from pytorch_toolbelt.utils import pytorch_toolbelt_deprecated
label_desc: Use image node_id 1 to create a new AbstractDecoder object from inherited base classes: nn, HasInputFeaturesSpecification, HasOutputFeaturesSpecification with example: obj = AbstractDecoder(input_spec)