Don’t have service model inherit from dict

Inheriting from `dict` has some unexpected side effects that don’t
happen with plain object. The one we want to avoid right now is that
a dict doesn’t seem to implement `__dict__` in a normal way, which
is required by `werkzeug.utils.cached_property`.

app/notify_client/models.py

@@ -268,7 +268,7 @@ class AnonymousUser(AnonymousUserMixin):
         return False
 
 
-class Service(dict):
+class Service():
 
     ALLOWED_PROPERTIES = {
         'active',
@@ -291,16 +291,30 @@ class Service(dict):
 
     def __init__(self, _dict):
         # in the case of a bad request current service may be `None`
-        super().__init__(_dict or {})
+        self._dict = _dict or {}
+        if 'permissions' not in self._dict:
+            self.permissions = {'email', 'sms', 'letter'}
+
+    def __bool__(self):
+        return self._dict != {}
 
     def __getattr__(self, attr):
         if attr in self.ALLOWED_PROPERTIES:
-            return self[attr]
+            return self._dict[attr]
         raise AttributeError('`{}` is not a service attribute'.format(attr))
 
+    def __getitem__(self, attr):
+        return self.__getattr__(attr)
+
+    def get(self, attr, default=None):
+        try:
+            return self._dict[attr]
+        except KeyError:
+            return default
+
     @property
     def trial_mode(self):
-        return self['restricted']
+        return self._dict['restricted']
 
     def has_permission(self, permission):
         return permission in self.permissions

app/templates/partials/check/too-many-messages.html

@@ -7,7 +7,7 @@
 </h1>
 <p>
   You can only send {{ current_service.message_limit }} messages per day
-  {%- if current_service.restricted %}
+  {%- if current_service.trial_mode %}
     in <a href="{{ url_for('.using_notify')}}#trial-mode">trial mode</a>
   {%- endif -%}
   .

app/templates/views/service-settings.html

@@ -253,7 +253,7 @@
       {% endcall %}
     </div>
 
-    {% if current_service.restricted %}
+    {% if current_service.trial_mode %}
       <h2 class="heading-medium">Your service is in trial mode</h2>
 
       <ul class='list list-bullet'>
@@ -334,7 +334,7 @@
       <ul>
         <li class="bottom-gutter">
           <a href="{{ url_for('.service_switch_live', service_id=current_service.id) }}" class="button">
-            {{ 'Make service live' if current_service.restricted else 'Revert service to trial mode' }}
+            {{ 'Make service live' if current_service.trial_mode else 'Revert service to trial mode' }}
           </a>
         </li>
         <li class="bottom-gutter">