class_docstr: Base class for heads that can be attached to :class:`ClassyModel`.
  
  A head is a regular :class:`torch.nn.Module` that can be attached to a
  pretrained model. This enables a form of transfer learning: utilizing a
  model trained for one dataset to extract features that can be used for
  other problems. A head must be attached to a :class:`models.ClassyBlock`
  within a :class:`models.ClassyModel`.
docstr: Instantiates a ClassyHead from a configuration.
  
  Args:
      config: A configuration for the ClassyHead.
  
  Returns:
      A ClassyHead instance.
docstr_tok: ["Instantiates","a","ClassyHead","from","a","configuration",".","Args",":","config",":","A","configuration","for","the","ClassyHead",".","Returns",":","A","ClassyHead","instance","."]
code: def from_config(cls, config: Dict[str, Any]) -> "ClassyHead":
      """Instantiates a ClassyHead from a configuration.
  
      Args:
          config: A configuration for the ClassyHead.
  
      Returns:
          A ClassyHead instance.
      """
      raise NotImplementedError
  
imports: from typing import Any, Dict, Optional
  import torch.nn
label_desc: Use image node_id 2 for calling the ClassyHead obj's underlying member method code with example usage: obj.from_config(cls, config) without return types