NameError: name 'NamedTemporaryFile' is not defined

when try to convert any python source file, appear this error
test python file [symbolic.py.txt](https://github.com/adsharma/py2many/files/6529267/symbolic.py.txt)

G:\work>py2many --rust=1 symbolic.py
Traceback (most recent call last):
  File "G:\tools\Anaconda3\Scripts\py2many-script.py", line 33, in <module>
    sys.exit(load_entry_point('py2many==0.2.1', 'console_scripts', 'py2many')())
  File "G:\tools\Anaconda3\Scripts\py2many-script.py", line 25, in importlib_load_entry_point
    return next(matches).load()
  File "G:\tools\Anaconda3\lib\importlib\metadata.py", line 77, in load
    module = import_module(match.group('module'))
  File "G:\tools\Anaconda3\lib\importlib\__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 783, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "G:\tools\Anaconda3\lib\site-packages\py2many-0.2.1-py3.8.egg\py2many\cli.py", line 23, in <module>
    from pyrs.transpiler import (
  File "G:\tools\Anaconda3\lib\site-packages\py2many-0.2.1-py3.8.egg\pyrs\transpiler.py", line 9, in <module>
    from .plugins import CLASS_DISPATCH_TABLE, FUNC_DISPATCH_TABLE, MODULE_DISPATCH_TABLE
  File "G:\tools\Anaconda3\lib\site-packages\py2many-0.2.1-py3.8.egg\pyrs\plugins.py", line 100, in <module>
    NamedTemporaryFile: RustTranspilerPlugins.visit_named_temp_file,
NameError: name 'NamedTemporaryFile' is not defined