AttributeError: 'Unparser' object has no attribute '_str'. Did you mean: '_Str'? pyflowchart 0.3.1 with python 3.11 and astunparse 1.6.3

[cdfmlr]

As pyflowchart 0.3.1 used with python 3.11 and astunparse 1.6.3 throws an exception:

Traceback (most recent call last):
  File "C:\Downloads\sc-navigator-model-generation-cp\APO Input Workflow\src\flowchart.py", line 12, in <module>
    fc = pfc.parse(code)
         ^^^^^^^^^^^^^^^
  File "C:\Downloads\sc-navigator-model-generation-cp\APO Input Workflow\src\new_env\Lib\site-packages\pyflowchart\ast_node.py", line 659, in parse
    node = ast_node_class(ast_object, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Downloads\sc-navigator-model-generation-cp\APO Input Workflow\src\new_env\Lib\site-packages\pyflowchart\ast_node.py", line 463, in __init__
    OperationNode.__init__(self, operation=self.ast_to_source())
                                           ^^^^^^^^^^^^^^^^^^^^
  File "C:\Downloads\sc-navigator-model-generation-cp\APO Input Workflow\src\new_env\Lib\site-packages\pyflowchart\ast_node.py", line 33, in ast_to_source
    return astunparse.unparse(self.ast_object).strip()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Downloads\sc-navigator-model-generation-cp\APO Input Workflow\src\new_env\Lib\site-packages\astunparse\__init__.py", line 13, in unparse
    Unparser(tree, file=v)
  File "C:\Downloads\sc-navigator-model-generation-cp\APO Input Workflow\src\new_env\Lib\site-packages\astunparse\unparser.py", line 38, in __init__
    self.dispatch(tree)
  File "C:\Downloads\sc-navigator-model-generation-cp\APO Input Workflow\src\new_env\Lib\site-packages\astunparse\unparser.py", line 65, in dispatch
    meth = getattr(self, "_"+tree.__class__.__name__)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'Unparser' object has no attribute '_str'. Did you mean: '_Str'?

How do I resolve this issue?

Originally posted by @kaasima10 in https://github.com/cdfmlr/pyflowchart/issues/28#issuecomment-2101265384