holzschu
%pip install backports.lzma || py7zr can’t be installed
When trying to install, starts but it says “Failed to build backports.lzma” and other case “Preparing metadata (pyproject.toml): finished with status 'error'”. After the error kernel starts to works odd, every time when re starting the kernel died and then starts again.
It's a bit more difficult to debug without the full error message, but backports.lzma tries to compile the lzma library and the xz command. Both of these require a compiler (to compile C source code and libraries), which does not exist on iOS. Hence they cannot be installed (only pure Python packages can be installed). Same with py7zr. You can use a-Shell to have the xz utility.
That being said, lzma is supposed to be included with Python versions after 3.3, so backports.lzma should not be necessary. I'll investigate.
If I had to guess, there's a pyproject.toml in some project, which is always installing backports.lzma even though it is only needed on Python 2 (and some fairly old Python 3.x versions). Ideally the pyproject.toml would conditionally (like 'backports.lzma; python_version<"3.3"'). Maybe worth asking that project if they would be open to this change?
