docstr: Store the pass class instead of instance to avoid the same instance got modified by several
  callers.
code: def __init__(self):
      """
      Store the pass class instead of instance to avoid the same instance got modified by several
      callers.
      """
      self.passes: Dict[Text, Type[AbstractGraphPass]] = {}
  
file_path: coremltools/coremltools/converters/mil/mil/passes/pass_registry.py
imports: import inspect
  from typing import Dict, Optional, Text, Type
  from coremltools import _logger
  from coremltools.converters.mil.mil.passes.graph_pass import AbstractGraphPass
label_desc: Use image node_id 1 to create a new PassRegistry object  with example: obj = PassRegistry()