class_docstr: Abstract base class of all serializers and deserializers.
docstr: Gets a child serializer.
  
  This operator creates a _child_ serializer represented by the given
  key.
  
  Args:
      key (str): Name of the child serializer.
code: def __getitem__(self, key):
      """Gets a child serializer.
  
      This operator creates a _child_ serializer represented by the given
      key.
  
      Args:
          key (str): Name of the child serializer.
  
      """
      raise NotImplementedError
  
file_path: chainer/chainer/serializer.py
label_desc: Use image node_id 1 for calling the AbstractSerializer obj's underlying member method code with example usage: obj.__getitem__(key) without return types