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

@@ -2,12 +2,12 @@
 # this repository contains the full copyright notices and license terms.
 
 from trytond.pool import Pool
-from .country import *
+from . import country
 
 
 def register():
     Pool.register(
-        Country,
-        Subdivision,
-        Zip,
+        country.Country,
+        country.Subdivision,
+        country.Zip,
         module='country', type_='model')

country.py

@@ -6,8 +6,6 @@ from trytond.pyson import Eval
 from trytond.transaction import Transaction
 from trytond.tools import lstrip_wildcard
 
-__all__ = ['Country', 'Subdivision', 'Zip']
-
 
 class Country(DeactivableMixin, ModelSQL, ModelView):
     'Country'

setup.py

@@ -79,8 +79,8 @@ setup(name=name,
     keywords='tryton country',
     package_dir={'trytond.modules.country': '.'},
     packages=(
-        ['trytond.modules.country'] +
-        ['trytond.modules.country.%s' % p for p in find_packages()]
+        ['trytond.modules.country']
+        + ['trytond.modules.country.%s' % p for p in find_packages()]
         ),
     package_data={
         'trytond.modules.country': (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)',
@@ -139,7 +140,7 @@ setup(name=name,
     [console_scripts]
     trytond_import_countries = trytond.modules.country.scripts.import_countries:run [data]
     trytond_import_zip = trytond.modules.country.scripts.import_zip:run [GeoNames]
-    """,
+    """,  # noqa: E501
     test_suite='tests',
     test_loader='trytond.test_loader:Loader',
     tests_require=tests_require,