class_docstr: The definition of an operation.
  
  This class contains all the information needed to run an operation, except
  the number of inputs and their values.  A subclass should document
  
    - How many inputs it expects, and what they should contain.
    - What it outputs, as a function of its inputs.
  
  An OperationDef is just a specification and does not contain the actual
  computation.
docstr: A unique label for this operation in the graph.
docstr_tok: ["A","unique","label","for","this","operation","in","the","graph","."]
code: def label(self) -> str:
      """A unique label for this operation in the graph."""
      pass
  
imports: import abc
  import collections
  import dataclasses
  from typing import Any, Collection, Dict, List, Optional, Tuple
  import pydot
label_desc: Use image node_id 2 for calling the OperationDef obj's underlying member method code with example usage: obj.label() without return types