Code style cleanups

Add keyword arguments. Sort arguments and models.
Move literals to their own module. Prepend handler_ to
signal handlers.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/common/classes.py

@@ -35,6 +35,13 @@ class Collection(object):
     def __str__(self):
         return force_text(self.label)
 
+    def _get_children(self):
+        if self._queryset:
+            return self._queryset
+        else:
+            if self._model:
+                return self._model.objects.all()
+
     def resolve(self):
         self.children = self._get_children()
         self.icon = self._icon
@@ -45,13 +52,6 @@ class Collection(object):
             self.url = reverse(viewname=self._link.view, args=self._link.args)
         return ''
 
-    def _get_children(self):
-        if self._queryset:
-            return self._queryset
-        else:
-            if self._model:
-                return self._model.objects.all()
-
 
 @python_2_unicode_compatible
 class ErrorLogNamespace(object):
@@ -62,9 +62,6 @@ class ErrorLogNamespace(object):
     def __str__(self):
         return force_text(self.label)
 
-    def create(self, obj, result):
-        obj.error_logs.create(namespace=self.name, result=result)
-
     def all(self):
         ErrorLogEntry = apps.get_model(
             app_label='common', model_name='ErrorLogEntry'
@@ -72,6 +69,9 @@ class ErrorLogNamespace(object):
 
         return ErrorLogEntry.objects.filter(namespace=self.name)
 
+    def create(self, obj, result):
+        obj.error_logs.create(namespace=self.name, result=result)
+
 
 class MissingItem(object):
     _registry = []
@@ -92,6 +92,12 @@ class MissingItem(object):
 class ModelAttribute(object):
     _registry = {}
 
+    @classmethod
+    def get_choices_for(cls, model):
+        return [
+            (attribute.name, attribute) for attribute in cls.get_for(model=model)
+        ]
+
     @classmethod
     def get_for(cls, model):
         try:
@@ -106,12 +112,6 @@ class ModelAttribute(object):
 
             return cls.get_for(model=type(model))
 
-    @classmethod
-    def get_choices_for(cls, model):
-        return [
-            (attribute.name, attribute) for attribute in cls.get_for(model)
-        ]
-
     @classmethod
     def get_help_text_for(cls, model, show_name=False):
         result = []
@@ -208,15 +208,6 @@ class ModelField(ModelAttribute):
 class ModelProperty(object):
     _registry = []
 
-    @classmethod
-    def get_for(cls, model):
-        result = []
-
-        for klass in cls._registry:
-            result.extend(klass.get_for(model=model))
-
-        return result
-
     @classmethod
     def get_choices_for(cls, model):
         result = []
@@ -226,6 +217,15 @@ class ModelProperty(object):
 
         return result
 
+    @classmethod
+    def get_for(cls, model):
+        result = []
+
+        for klass in cls._registry:
+            result.extend(klass.get_for(model=model))
+
+        return result
+
     @classmethod
     def get_help_text_for(cls, model, show_name=False):
         result = []
@@ -324,5 +324,5 @@ class Template(object):
         return self
 
 
-ModelProperty.register(ModelAttribute)
-ModelProperty.register(ModelField)
+ModelProperty.register(klass=ModelAttribute)
+ModelProperty.register(klass=ModelField)