invalid imports in the documentation

[BALOGHBence]

The examples in the documentation ofter point to invalid references. For instance, the following imports

from sectionproperties.pre import Material
from sectionproperties.pre.library import i_section
from sectionproperties.analysis import Section

should be

from sectionproperties.pre.pre import Material
from sectionproperties.pre.library.steel_sections import i_section
from sectionproperties.analysis.section import Section

These could be avoided by either populating the init.py files or correcting the examples in the docs.

At the 'Results' section of the User Guide, the reference to the function plot_stress is invalid.

[github-actions[bot]]

Thanks for opening your first issue in sectionproperties :raised_hands: Pull requests are always welcome :wink:

[robbievanleeuwen]

Hi @BALOGHBence, are you getting any import errors? The __init__.py files already contain these references so they should work. This was introduced recently in v3.0.0 to improve readability (see features).

I cannot find the invalid reference to plot stress, could you clarify this?

[BALOGHBence]

Hi. I think the problem here is that I used the package under Python 3.8. I can see now that version 3.0.0 is only from Python 3.9.