Small fixes

[ale-rt]

Better reviewd commit by commit

[mister-roboto]

@ale-rt thanks for creating this Pull Request and helping to improve Plone!

TL;DR: Finish pushing changes, pass all other checks, then paste a comment:

@jenkins-plone-org please run jobs

To ensure that these changes do not break other parts of Plone, the Plone test suite matrix needs to pass, but it takes 30-60 min. Other CI checks are usually much faster and the Plone Jenkins resources are limited, so when done pushing changes and all other checks pass either start all Jenkins PR jobs yourself, or simply add the comment above in this PR to start all the jobs automatically.

Happy hacking!

[ale-rt]

@jenkins-plone-org please run jobs

[mauritsvanrees]

LGTM, thanks.
I added two inline comments, but they can be ignored. I will merge.

[mauritsvanrees]

Py23DocChecker could also be removed. But can be done later.

[ale-rt]

Py23DocChecker is removed in #32

[mauritsvanrees]

I don't think we are running flake8 anymore. Just black. But it does not hurt.
I myself have a small custom script to call flake8 and ignore a few common problems:

$ cat ~/bin/pychecker3
#! /bin/sh
#infile = $1
if test "x$1" = "x--stdlib"; then
    # --stdlib gets passed by some python-mode.el versions.  pep8 and
    # pyflakes and flake8 cannot handle this, so we ignore this argument, by
    # shifting the rest of the arguments.
    #shift
    # Actually, we suddenly get passed 'pychecker --stdlib /Volumes/Macintosh /Volumes/Macintosh /Volumes/Macintosh /Volumes/Macintosh /Volumes/Macintosh /Users/mauritsvanrees/myfile.py'
    # So we shift to the last argument and pass only that
    shift $(($# - 1))
fi
# Check with Python 3.
# E203 Whitespace before ':' (false positives when using black)
# E231 missing whitespace after ',' (conflicts with black)
# E501 line too long
# W503 Line break occurred before a binary operator [outdated]
flake8 --ignore=E203,E231,E501,W503 $1 | sort-flake8

And then sort-flake8:

#!/usr/bin/env python
# Example: flake8 zest/releaser/utils.py | ./pychecker-sort
# Sorts with Failures first.
import sys
lines = sys.stdin.read().splitlines()


def get_code(line):
    """Extract error code from line.

    Example line:
    'zest/releaser/utils.py:797:1: E302 expected 2 blank lines, found 1'
    """
    if line.count(':') != 3:
        return ''
    filename, lineno, pos, error = line.split(':')
    # Example error:
    # ' E302 expected 2 blank lines, found 1'
    code = error.strip().split(' ', 1)[0]
    if not code:
        return ''
    return code


def sortable_code(code):
    """Make code sortable.

    First failures, then errors, then warnings, then any others.
    """
    if not code:
        # sort last
        return '9'
    first = code[0]
    if first == 'F':
        value = 0
    elif first == 'E':
        value = 1
    elif first == 'W':
        value = 2
    else:
        value = 3
    return '{}{}'.format(value, code)


def error_value(line):
    return sortable_code(get_code(line))


for line in sorted(lines, key=error_value):
    print(line)