pep8 fixes

- B007 Loop control variable not used within the loop body. If this is intended, start the name with an underscore.
    * modoboa/admin/lib.py
    * modoboa/admin/templatetags/admin_tags.py
    * modoboa/admin/tests/test_account.py
    * modoboa/admin/views/domain.py
    * modoboa/admin/views/identity.py
    * modoboa/core/views/dashboard.py
    * modoboa/limits/forms.py
    * modoboa/limits/handlers.py
    * modoboa/limits/tests/test_api.py
    * modoboa/limits/tests/test_domain_limits.py
    * modoboa/limits/tests/test_import.py
    * modoboa/limits/tests/test_user_limits.py
    * modoboa/limits/utils.py
    * modoboa/parameters/tools.py
    * modoboa/relaydomains/tests.py
- C402 Unnecessary generator - rewrite as a dict comprehension.
    * modoboa/admin/models/domain.py
    * modoboa/admin/views/domain.py
    * modoboa/admin/views/identity.py
    * modoboa/limits/searializers.py
- C407 Unnecessary list comprehension - can take a generator.
    * modoboa/core/password_validation.py
    * modoboa/parameters/tools.py
    * modoboa/transport/backends.py
- C408 Unnecessary dict call - rewrite as a literal.
    * modoboa/admin/tests/test_account.py
    * modoboa/admin/tests/test_alias.py
    * modoboa/admin/tests/test_password_schemes.py
    * modoboa/admin/views/domain.py
    * modoboa/admin/views/identity.py
    * modoboa/core/extensions.py
    * modoboa/lib/middleware.py
    * modoboa/lib/templatetags/form_tags.py
    * modoboa/lib/templatetags/lib_tags.py
    * modoboa/lib/web_utils.py
    * modoboa/limits/handlers.py
    * modoboa/limits/tests/test_user_limits.py
- E741 ambiguous variable name
    * modoboa/core/management/commands/cleanlogs.py
    * modoboa/limits/forms.py
    * modoboa/limits/tests/test_user_limits.py
    * modoboa/limits/utils.py
    * modoboa/relaydomains/tests.py
- F401 imported but unused
    * doc/conf.py
    * modoboa/admin/views/domain.py
    * modoboa/core/app_settings.py
    * modoboa/core/management/commands/load_initial_data.py
- F821 undefined name 'raw_input'
    * modoboa/core/commands/deploy.py
- F841 local variable 'test' is assigned to but never used
    * modoboa/core/app_settings.py
- N802 function name 'setUpTestData' should be lowercase xxx
    * modoboa/lib/email_utils.py - __ for name mangeling, _ for internal
- N805 first argument of a method should be named 'self'
    * modoboa/lib/connections.py
    * modoboa/lib/singleton.py

Ignore the following
- A001 "copyright" is a python builtin and is being shadowed, consider renaming the variable
    * doc/conf.py
- A003 is a python builtin, consider renaming the class attribute
    * modoboa/admin/factories.py
    * modoboa/admin/forms/domain.py
    * modoboa/admin/management/commands/handle_mailbox_operations.py
    * modoboa/admin/management/commands/modo.py
    * modoboa/admin/management/commands/subcommands/_repair.py
    * modoboa/admin/models/domain.py
    * modoboa/admin/models/mailbox.py
    * modoboa/core/commands/__init__.py
    * modoboa/core/commands/deploy.py
    * modoboa/core/commands/help.py
    * modoboa/core/management/commands/clean_inactive_accounts.py
    * modoboa/core/management/commands/cleanlogs.py
    * modoboa/core/management/commands/communicate_with_public_api.py
    * modoboa/core/management/commands/generate_postfix_maps.py
    * modoboa/core/management/commands/load_initial_data.py
    * modoboa/core/management/commands/set_default_site.py
- F401 imported but unused
    * modoboa/admin/apps.py - used to load handlers
    * modoboa/core/password_hashers/__init__.py - dynamically loaded
    * modoboa/limits/apps.py - used to load handlers
    * modoboa/relaydomains/apps.py - used to load handlers
    * modoboa/transport/apps.py - used to load handlers
- N802 function name should be lowercase xxx
    * modoboa/admin/tests/test_account.py
    * modoboa/admin/tests/test_alias.py
    * modoboa/admin/tests/test_domain_alias.py
    * modoboa/admin/tests/test_export.py
    * modoboa/admin/tests/test_mailbox_operations.py
    * modoboa/admin/tests/test_password_schemas.py
    * modoboa/admin/tests/test_repair.py
    * modoboa/core/tests/test_authentication.py
    * modoboa/core/tests/test_core.py
    * modoboa/core/tests/test_ldap.py
    * modoboa/core/tests/test_views.py
    * modoboa/lib/imap_utf7.py
    * modoboa/limits/tests/test_api.py
    * modoboa/limits/tests/test_domain_limits.py
    * modoboa/limits/tests/test_import.py
    * modoboa/limits/tests/test_user_limits.py
    * modoboa/relaydomains/tests.py

other fixes:
- use isinstance() instead of type() == Class

modoboa/parameters/forms.py

@@ -70,7 +70,7 @@ class AdminParametersForm(GenericParametersForm):
         """Save parameters to database."""
         parameters = {}
         for name, value in list(self.cleaned_data.items()):
-            if type(self.fields[name]) is form_utils.SeparatorField:
+            if isinstance(self.fields[name], form_utils.SeparatorField):
                 continue
             parameters[name] = value
         self.localconfig.parameters.set_values(parameters, app=self.app)
@@ -101,7 +101,7 @@ class UserParametersForm(GenericParametersForm):
         """Save new values."""
         parameters = {}
         for name, value in list(self.cleaned_data.items()):
-            if type(self.fields[name]) is form_utils.SeparatorField:
+            if isinstance(self.fields[name], form_utils.SeparatorField):
                 continue
             parameters[name] = value
         self.user.parameters.set_values(parameters, app=self.app)

modoboa/parameters/tests.py

@@ -1,5 +0,0 @@
-from __future__ import unicode_literals
-
-from django.test import TestCase
-
-# Create your tests here.

modoboa/parameters/tools.py

@@ -42,10 +42,10 @@ class Registry(object):
 
     def _load_default_values(self, level):
         """Load default values."""
-        for app, data in list(self._registry[level].items()):
+        for _app, data in list(self._registry[level].items()):
             form = data["formclass"](load_values_from_db=False)
             for name, field in list(form.fields.items()):
-                if type(field) is form_utils.SeparatorField:
+                if isinstance(field, form_utils.SeparatorField):
                     continue
                 data["defaults"][name] = field.initial
 
@@ -56,8 +56,10 @@ class Registry(object):
         if first_app in self._registry[level]:
             sorted_apps.append(first_app)
         sorted_apps += sorted(
-            [a for a in list(self._registry[level].keys())
-             if a != first_app],
+            (
+                a for a in self._registry[level]
+                if a != first_app
+            ),
             key=lambda a: self._registry[level][a]["label"]
         )
         result = []