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

@@ -11,6 +11,6 @@ def register():
         work.Work,
         module='project_revenue', type_='model')
     Pool.register(
-        purchase.PurchaseLine,
+        purchase.Line,
         module='project_revenue', type_='model',
         depends=['purchase'])

purchase.py

@@ -4,10 +4,8 @@ from trytond.pool import PoolMeta
 from trytond.model import fields
 from trytond.pyson import Eval
 
-__all__ = ['PurchaseLine']
 
-
-class PurchaseLine(metaclass=PoolMeta):
+class Line(metaclass=PoolMeta):
     __name__ = 'purchase.line'
 
     work = fields.Many2One('project.work', 'Work Effort', select=True,

setup.py

@@ -80,8 +80,8 @@ setup(name=name,
     keywords='tryton project revenue',
     package_dir={'trytond.modules.project_revenue': '.'},
     packages=(
-        ['trytond.modules.project_revenue'] +
-        ['trytond.modules.project_revenue.%s' % p for p in find_packages()]
+        ['trytond.modules.project_revenue']
+        + ['trytond.modules.project_revenue.%s' % p for p in find_packages()]
         ),
     package_data={
         'trytond.modules.project_revenue': (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)',

tests/__init__.py

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

work.py

@@ -14,8 +14,6 @@ from trytond.tools import reduce_ids, grouped_slice
 
 from trytond.modules.product import price_digits
 
-__all__ = ['Work']
-
 
 class Work(metaclass=PoolMeta):
     __name__ = 'project.work'