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BlandCorporation
Asked: 2019-01-05 06:50:56 +0800 CST

SyntaxError regarding async when attempting to run Jupyter in Python 3.7

  • 772

On attempting to launch Jupyter on Python 3.7, I observe the following:

$ jupyter notebook
Traceback (most recent call last):
  File "/usr/local/bin/jupyter-notebook", line 11, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.7/dist-packages/jupyter_core/application.py", line 266, in launch_instance
    return super(JupyterApp, cls).launch_instance(argv=argv, **kwargs)
  File "/usr/local/lib/python3.7/dist-packages/traitlets/config/application.py", line 657, in launch_instance
    app.initialize(argv)
  File "<decorator-gen-7>", line 2, in initialize
  File "/usr/local/lib/python3.7/dist-packages/traitlets/config/application.py", line 87, in catch_config_error
    return method(app, *args, **kwargs)
  File "/usr/local/lib/python3.7/dist-packages/notebook/notebookapp.py", line 1629, in initialize
    self.init_webapp()
  File "/usr/local/lib/python3.7/dist-packages/notebook/notebookapp.py", line 1379, in init_webapp
    self.jinja_environment_options,
  File "/usr/local/lib/python3.7/dist-packages/notebook/notebookapp.py", line 158, in __init__
    default_url, settings_overrides, jinja_env_options)
  File "/usr/local/lib/python3.7/dist-packages/notebook/notebookapp.py", line 270, in init_settings
    nbextensions_path=jupyter_app.nbextensions_path,
  File "/usr/local/lib/python3.7/dist-packages/notebook/notebookapp.py", line 1066, in nbextensions_path
    from IPython.paths import get_ipython_dir
  File "/usr/local/lib/python3.7/dist-packages/IPython/__init__.py", line 54, in <module>
    from .core.application import Application
  File "/usr/local/lib/python3.7/dist-packages/IPython/core/application.py", line 25, in <module>
    from IPython.core import release, crashhandler
  File "/usr/local/lib/python3.7/dist-packages/IPython/core/crashhandler.py", line 27, in <module>
    from IPython.core import ultratb
  File "/usr/local/lib/python3.7/dist-packages/IPython/core/ultratb.py", line 119, in <module>
    from IPython.utils import path as util_path
  File "/usr/local/lib/python3.7/dist-packages/IPython/utils/path.py", line 17, in <module>
    from IPython.utils.process import system
  File "/usr/local/lib/python3.7/dist-packages/IPython/utils/process.py", line 19, in <module>
    from ._process_posix import system, getoutput, arg_split, check_pid
  File "/usr/local/lib/python3.7/dist-packages/IPython/utils/_process_posix.py", line 23, in <module>
    import pexpect
  File "/usr/lib/python3/dist-packages/pexpect/__init__.py", line 75, in <module>
    from .pty_spawn import spawn, spawnu
  File "/usr/lib/python3/dist-packages/pexpect/pty_spawn.py", line 15, in <module>
    from .spawnbase import SpawnBase
  File "/usr/lib/python3/dist-packages/pexpect/spawnbase.py", line 218
    def expect(self, pattern, timeout=-1, searchwindowsize=-1, async=False):
                                                                   ^
SyntaxError: invalid syntax

I've installed python3.7-distutils (which appears to feature pexpect) and I've reinstalled Jupyter using pip3, yet I still see this error. I've also uninstalled and reinstalled the following packages:

python3.7 python3.7-dev python3.7-distutils python3.7-tk

What should be done?

I see reference to this fix but, assuming it is a fix, don't know how to get it up and running on this 16.04 LTS install.

EDIT: On importing pexpect in Python 3.7, I get the same sort of thing:

>>> import pexpect
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3/dist-packages/pexpect/__init__.py", line 75, in <module>
    from .pty_spawn import spawn, spawnu
  File "/usr/lib/python3/dist-packages/pexpect/pty_spawn.py", line 15, in <module>
    from .spawnbase import SpawnBase
  File "/usr/lib/python3/dist-packages/pexpect/spawnbase.py", line 218
    def expect(self, pattern, timeout=-1, searchwindowsize=-1, async=False):
                                                                   ^
SyntaxError: invalid syntax
python3 16.04 jupyter

5 Answers

  1. For me, it was conflicting with apt-get installed python3, so I had to first uninstall it/them:

    sudo apt-get remove python-pexpect python3-pexpect

    And then

    sudo pip3.7 install --upgrade pexpect

    • 11

  2. Download pexpect4.6 source code from https://github.com/pexpect/pexpect/releases/tag/4.6

    Extract the source code, get into the folder and install the pexpect by:

    sudo python3.7 setup.py install

    This should solve your problem. :)

    • 1

  3. I had the same problem and the following steps worked for me.

    I went to /usrlib/python3/dist-packages/pexpect/ and there I

    • renamed async.py to _async.py
    • opened spawn.py and made these replacements: 
      'async=' -> 'async_='
'async:'-> 'async_:'
'.async' -> '._async'

    Hope it helps someone else, too.

    • 1

  4. I was getting the same error. I've tried to:

    python3.7 -c 'import pexpect'

    And I got:

    Traceback (most recent call last):   File "<string>", line 1, in <module>   File "/usr/lib/python3/dist-packages/pexpect/__init__.py", line 75, in <module>
    from .pty_spawn import spawn, spawnu   File "/usr/lib/python3/dist-packages/pexpect/pty_spawn.py", line 14, in <module>
    from .spawnbase import SpawnBase   File "/usr/lib/python3/dist-packages/pexpect/spawnbase.py", line 224
    def expect(self, pattern, timeout=-1, searchwindowsize=-1, async=False):
                                                                   ^ SyntaxError: invalid syntax Error in sys.excepthook: Traceback (most recent call last):   File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 63, in apport_excepthook
    from apport.fileutils import likely_packaged, get_recent_crashes   File "/usr/lib/python3/dist-packages/apport/__init__.py", line 5, in <module>
    from apport.report import Report   File "/usr/lib/python3/dist-packages/apport/report.py", line 30, in <module>
    import apport.fileutils   File "/usr/lib/python3/dist-packages/apport/fileutils.py", line 23, in <module>
    from apport.packaging_impl import impl as packaging   File "/usr/lib/python3/dist-packages/apport/packaging_impl.py", line 24, in <module>
    import apt   File "/usr/lib/python3/dist-packages/apt/__init__.py", line 23, in <module>
    import apt_pkg ModuleNotFoundError: No module named 'apt_pkg'

Original exception was: Traceback (most recent call last):   File "<string>", line 1, in <module>   File "/usr/lib/python3/dist-packages/pexpect/__init__.py", line 75, in <module>
    from .pty_spawn import spawn, spawnu   File "/usr/lib/python3/dist-packages/pexpect/pty_spawn.py", line 14, in <module>
    from .spawnbase import SpawnBase   File "/usr/lib/python3/dist-packages/pexpect/spawnbase.py", line 224
    def expect(self, pattern, timeout=-1, searchwindowsize=-1, async=False):
                                                                   ^ 
SyntaxError: invalid syntax

    After that I tried:

    pip3 install pexpect

    Now jupyter works just fine.

    • 0
  5. Best Answer

    I faced this problem while running django tests. Upgrade the version to the latest at the time (4.8), fixed the issue.

    • 0