Fix flake8 errors and warnings

We add the flake8 configuration used so we ensure everyone uses the same.
We remove the usage of __all__ for non public API.
When possible, we rationalize the class name according to its __name__ and module.

issue9082
review297061002

.flake8

@@ -0,0 +1,2 @@
+[flake8]
+ignore=E123,E124,E126,E128,W503

__init__.py

@@ -3,14 +3,14 @@
 
 from trytond.pool import Pool
 
-from .production import *
+from . import production
 
 
 def register():
     Pool.register(
-        Production,
-        SplitProductionStart,
+        production.Production,
+        production.SplitProductionStart,
         module='production_split', type_='model')
     Pool.register(
-        SplitProduction,
+        production.SplitProduction,
         module='production_split', type_='wizard')

production.py

@@ -6,8 +6,6 @@ from trytond.pyson import Eval
 from trytond.transaction import Transaction
 from trytond.wizard import Wizard, StateView, StateTransition, Button
 
-__all__ = ['Production', 'SplitProduction', 'SplitProductionStart']
-
 
 class Production(metaclass=PoolMeta):
     __name__ = 'production'

setup.py

@@ -79,8 +79,9 @@ setup(name=name,
     keywords='tryton production split',
     package_dir={'trytond.modules.production_split': '.'},
     packages=(
-        ['trytond.modules.production_split'] +
-        ['trytond.modules.production_split.%s' % p for p in find_packages()]
+        ['trytond.modules.production_split']
+        + ['trytond.modules.production_split.%s' % p
+            for p in find_packages()]
         ),
     package_data={
         'trytond.modules.production_split': (info.get('xml', [])
@@ -94,7 +95,8 @@ setup(name=name,
         'Intended Audience :: Developers',
         'Intended Audience :: Financial and Insurance Industry',
         'Intended Audience :: Legal Industry',
-        'License :: OSI Approved :: GNU General Public License v3 or later (GPLv3+)',
+        'License :: OSI Approved :: '
+        'GNU General Public License v3 or later (GPLv3+)',
         'Natural Language :: Bulgarian',
         'Natural Language :: Catalan',
         'Natural Language :: Czech',

tests/__init__.py

@@ -2,7 +2,7 @@
 # this repository contains the full copyright notices and license terms.
 
 try:
-    from trytond.modules.production_split.tests.test_production_split import suite
+    from trytond.modules.production_split.tests.test_production_split import suite  # noqa: E501
 except ImportError:
     from .test_production_split import suite