Keep imports alphabetically sorted and their order homogeneous across
Python source files.
The isort project has more feature and is more active than the
flake8-import-order plugin.
Most issues caught were simply import ordering from the same module.
Where imports were purposefully placed out of order, tag with
isort:skip.
Refs: #6890
The comma character is not TeX-escaped because it is frequent in general
text and escaping it would make the LaTeX output larger for only dealing
with the problem of the LaTeX-ligature of ,, into a single character.
And one there is problem with the commas in options to Verbatim from
PygmentsBridge.
The hyphen character is escaped (not in ids and URIs!) to
\sphinxhyphen{} for both Unicode and non-Unicode engines. This is needed
to work around hyperref transforming -- and --- from section titles into
EN DASH resp. EM DASH in PDF bookmarks.
https://github.com/latex3/hyperref/issues/112
Note to expert LaTeX users: if Sphinx latex user with xelatex has
- turned off Smart Quotes for some reason,
- but does want TeX ligatures and thus overrode Sphinx
latex_elements['fontenc'] default (since #6888) to this effect,
then this should be added to LaTeX preamble:
\def\sphinxhyphen#1{-}% (\protected is now not needed)
\let\sphinxhyphenforbookmarks\sphinxhyphen
The Python docs for __import__ recommend using importlib.get_module().
https://docs.python.org/3/library/functions.html#__import__
> Note: This is an advanced function that is not needed in everyday
> Python programming, unlike importlib.import_module().
As importlib.get_module() uses the Python module cache and returns the
module, this also allows simplifying many module cache checks of use of
sys.modules.
importlib.get_module() has been available since Python 3.3.
In Python 3, the default encoding of source files is utf-8. The encoding
cookie is now unnecessary and redundant so remove it. For more details,
see the docs:
https://docs.python.org/3/howto/unicode.html#the-string-type
> The default encoding for Python source code is UTF-8, so you can
> simply include a Unicode character in a string literal ...
Includes a fix for the flake8 header checks to stop expecting an
encoding cookie.
