pip install

[kohlhase]

first, in the README "direct pip" install should be described first

When I did that, I get

... graphviz 2.40.1 is already installed and up-to-date
MiKo:~ kohlhase$ which gf
/usr/local/bin/gf
MiKo:~ kohlhase$ pip install gf-kernel
DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7.
Collecting gf-kernel
  Downloading https://files.pythonhosted.org/packages/26/29/f221fa1da96bbd93180fed121f83e02230a579b12b48433d2bdf3e63fe1b/gf_kernel-1.0.0.tar.gz
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/private/var/folders/9d/vk8_ls9d0_v0_bb4g7ncx90c0000gn/T/pip-install-S5rNLV/gf-kernel/setup.py", line 6, in <module>
        with open(path.join(this_directory, 'README.md'), encoding='utf-8') as f:
    TypeError: 'encoding' is an invalid keyword argument for this function
    
    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /private/var/folders/9d/vk8_ls9d0_v0_bb4g7ncx90c0000gn/T/pip-install-S5rNLV/gf-kernel/

I have python3 installed.

[kohlhase]

pip3 install gf-kernal did the trick.
I think the README should be updated with a python2/3 caveat.
My homebrew installation is the default one for python, and there must be other users like me.

[kohlhase]

Morever, trying to follow the installation with python3 (guessed) I get

MiKo:~ kohlhase$ python3 -m gf_kernel.install
/usr/local/bin/python3: Error while finding module specification for 'gf_kernel.install' (ModuleNotFoundError: No module named 'gf_kernel')

even though the gf-kernel seems to be there.

MiKo:~ kohlhase$ pip3 search gf-kernel
gf-kernel (1.0.0)                                - Simple example kernel for GF
  INSTALLED: 1.0.0 (latest)

[jfschaefer]

Concerning the first issue that pip might be linked to pip2: Is it possible to create a more meaningful error message if the wrong python version is used?

[kohlhase]

Is it possible to create a more meaningful error message if the wrong python version is used?

I do not know how.

[tkw1536]

1. The README says:

This package requires Python 3 (or newer) and this README assumes that this is the default python version. If in doubt, use python3 instead of python and python3 -m pip instead of pip.

is that not clear enough?

2. I am not sure what is going on in the second case, I can not reproduce this on my machine. Could it be that the pip problems caused errors while installing?

[step21]

The secod case might very well be that there are conflicting python versions, they are running one but module is installed somewhere else. People unfortunately have to organize their python versions themselves or use virtualnv or similar.