class_docstr: Base class for a graph pass.
  
  Each graph pass should be a subclass of this and implement the `apply` method.
  Each graph pass can also implement their own supported options.
  See examples of `skip_ops_by_type` in `add_fp16_cast` and `skip_const_by_size` in
  `const_elimination` about how to support new options in each pass.
code: def __str__(self):
      return type(self).__name__
  
file_path: coremltools/coremltools/converters/mil/mil/passes/graph_pass.py
imports: from abc import ABC, abstractmethod
  from typing import Callable, List, Optional, Text, Union
  from coremltools.converters.mil import Operation, Program
label_desc: Use image node_id 2 for calling the AbstractGraphPass obj's underlying member method code with example usage: obj.__str__() and returns: type