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

@@ -2,25 +2,30 @@
 # this repository contains the full copyright notices and license terms.
 
 from trytond.pool import Pool
-from .uom import *
-from .category import *
-from .product import *
-from .configuration import *
+from . import uom
+from . import category
+from . import product
+from . import configuration
+from .product import price_digits
+from .uom import uom_conversion_digits
+
+__all__ = [price_digits, uom_conversion_digits]
 
 
 def register():
     Pool.register(
-        UomCategory,
-        Uom,
-        Category,
-        Template,
-        Product,
-        ProductIdentifier,
-        ProductListPrice,
-        ProductCostPriceMethod,  # before ProductCostPrice for migration
-        ProductCostPrice,
-        TemplateCategory,
-        TemplateCategoryAll,
-        Configuration,
-        ConfigurationDefaultCostPriceMethod,
+        uom.UomCategory,
+        uom.Uom,
+        category.Category,
+        product.Template,
+        product.Product,
+        product.ProductIdentifier,
+        product.ProductListPrice,
+        # before ProductCostPrice for migration
+        product.ProductCostPriceMethod,
+        product.ProductCostPrice,
+        product.TemplateCategory,
+        product.TemplateCategoryAll,
+        configuration.Configuration,
+        configuration.ConfigurationDefaultCostPriceMethod,
         module='product', type_='model')

category.py

@@ -2,8 +2,6 @@
 # this repository contains the full copyright notices and license terms.
 from trytond.model import ModelView, ModelSQL, fields, tree
 
-__all__ = ['Category']
-
 
 class Category(tree(separator=' / '), ModelSQL, ModelView):
     "Product Category"

configuration.py

@@ -6,7 +6,6 @@ from trytond.model import (ModelView, ModelSQL, ModelSingleton,
 from trytond.pool import Pool
 from trytond.tools.multivalue import migrate_property
 
-__all__ = ['Configuration', 'ConfigurationDefaultCostPriceMethod']
 default_cost_price_method = fields.Selection(
     'get_cost_price_methods', "Default Cost Method")
 

product.py

@@ -25,9 +25,7 @@ from trytond.modules.company.model import (
 from .exceptions import InvalidIdentifierCode
 
 
-__all__ = ['Template', 'Product', 'price_digits', 'TemplateFunction',
-    'ProductListPrice', 'ProductCostPriceMethod', 'ProductCostPrice',
-    'TemplateCategory', 'TemplateCategoryAll', 'ProductIdentifier']
+__all__ = ['price_digits', 'TemplateFunction']
 logger = logging.getLogger(__name__)
 
 STATES = {
@@ -450,7 +448,8 @@ class ProductCostPriceMethod(ModelSQL, CompanyValueMixin):
         cursor = Transaction().connection.cursor()
 
         exist = backend.TableHandler.table_exist(cls._table)
-        cost_price_exist = backend.TableHandler.table_exist(ProductCostPrice._table)
+        cost_price_exist = backend.TableHandler.table_exist(
+            ProductCostPrice._table)
 
         super(ProductCostPriceMethod, cls).__register__(module_name)
 

setup.py

@@ -79,8 +79,8 @@ setup(name=name,
     keywords='tryton product',
     package_dir={'trytond.modules.product': '.'},
     packages=(
-        ['trytond.modules.product'] +
-        ['trytond.modules.product.%s' % p for p in find_packages()]
+        ['trytond.modules.product']
+        + ['trytond.modules.product.%s' % p for p in find_packages()]
         ),
     package_data={
         'trytond.modules.product': (info.get('xml', [])
@@ -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)',

uom.py

@@ -13,7 +13,7 @@ from trytond.transaction import Transaction
 
 from .exceptions import UOMValidationError
 
-__all__ = ['UomCategory', 'Uom', 'uom_conversion_digits']
+__all__ = ['uom_conversion_digits']
 
 STATES = {
     'readonly': ~Eval('active', True),