class_docstr: Main class from which all Flows should inherit.
  
  Attributes
  ----------
  index
  input
code: def __getstate__(self):
      raise MetaflowException(
          "Flows can't be serialized. Maybe you tried "
          "to assign *self* or one of the *inputs* "
          "to an attribute? Instead of serializing the "
          "whole flow, you should choose specific "
          "attributes, e.g. *input.some_var*, to be "
          "stored."
      )
  
imports: import inspect
  import os
  import sys
  import traceback
  from itertools import islice
  from types import FunctionType, MethodType
  from typing import Any, Callable, List, Optional, Tuple
  from .None import cmd_with_io
  from .parameters import DelayedEvaluationParameter, Parameter
  from .exception import MetaflowException, MissingInMergeArtifactsException, UnhandledInMergeArtifactsException
  from .graph import FlowGraph
  from .unbounded_foreach import UnboundedForeachInput
  from .datastore.inputs import Inputs
label_desc: Use image node_id 17 for calling the FlowSpec obj's underlying member method code with example usage: obj.__getstate__() without return types