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

product.py

@@ -4,8 +4,6 @@ from datetime import timedelta
 
 from trytond.pool import Pool, PoolMeta
 
-__all__ = ['Product']
-
 
 class Product(metaclass=PoolMeta):
     __name__ = 'product.product'

production.py

@@ -8,7 +8,6 @@ from trytond.pool import Pool, PoolMeta
 from trytond.transaction import Transaction
 from trytond.tools import grouped_slice
 
-__all__ = ['Configuration', 'ConfigurationSupplyPeriod', 'Production']
 supply_period = fields.TimeDelta("Supply Period")
 
 

setup.py

@@ -79,8 +79,8 @@ setup(name=name,
     keywords='tryton stock supply production',
     package_dir={'trytond.modules.stock_supply_production': '.'},
     packages=(
-        ['trytond.modules.stock_supply_production'] +
-        ['trytond.modules.stock_supply_production.%s' % p
+        ['trytond.modules.stock_supply_production']
+        + ['trytond.modules.stock_supply_production.%s' % p
             for p in find_packages()]
         ),
     package_data={
@@ -95,7 +95,8 @@ setup(name=name,
         'Intended Audience :: Financial and Insurance Industry',
         'Intended Audience :: Legal Industry',
         'Intended Audience :: Manufacturing',
-        '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 :: Chinese (Simplified)',

stock.py

@@ -9,8 +9,6 @@ from trytond.wizard import StateAction
 
 from trytond.modules.stock_supply.exceptions import SupplyWarning
 
-__all__ = ['OrderPoint', 'LocationLeadTime', 'StockSupply']
-
 
 class OrderPoint(metaclass=PoolMeta):
     __name__ = 'stock.order_point'

tests/__init__.py

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