Decouple the set of org types from their labels

In response to: [^1].

[^1]: https://github.com/alphagov/notifications-admin/pull/4196#discussion_r838383086

app/main/forms.py

@@ -992,7 +992,7 @@ class OrganisationTypeField(GovukRadiosField):
         super().__init__(
             *args,
             choices=[
-                (value, label) for value, label in Organisation.TYPES
+                (value, label) for value, label in Organisation.TYPE_LABELS.items()
                 if not include_only or value in include_only
             ],
             thing='the type of organisation',

app/models/organisation.py

@@ -1,3 +1,5 @@
+from collections import OrderedDict
+
 from flask import abort
 from werkzeug.utils import cached_property
 
@@ -24,19 +26,21 @@ class Organisation(JSONModel, SortByNameMixin):
     TYPE_OTHER = 'other'
 
     NHS_TYPES = (
+        TYPE_NHS_CENTRAL,
+        TYPE_NHS_LOCAL,
+        TYPE_NHS_GP,
+    )
+
+    TYPE_LABELS = OrderedDict([
+        (TYPE_CENTRAL, 'Central government'),
+        (TYPE_LOCAL, 'Local government'),
         (TYPE_NHS_CENTRAL, 'NHS – central government agency or public body'),
         (TYPE_NHS_LOCAL, 'NHS Trust or Clinical Commissioning Group'),
         (TYPE_NHS_GP, 'GP practice'),
-    )
-
-    TYPES = (
-        (TYPE_CENTRAL, 'Central government'),
-        (TYPE_LOCAL, 'Local government'),
-    ) + NHS_TYPES + (
         (TYPE_EMERGENCY_SERVICE, 'Emergency service'),
         (TYPE_SCHOOL_OR_COLLEGE, 'School or college'),
         (TYPE_OTHER, 'Other'),
-    )
+    ])
 
     ALLOWED_PROPERTIES = {
         'id',
@@ -112,7 +116,7 @@ class Organisation(JSONModel, SortByNameMixin):
 
     @property
     def organisation_type_label(self):
-        return dict(self.TYPES).get(self.organisation_type)
+        return self.TYPE_LABELS.get(self.organisation_type)
 
     @property
     def crown_status_or_404(self):

app/models/service.py

@@ -519,7 +519,7 @@ class Service(JSONModel, SortByNameMixin):
 
     @property
     def organisation_type_label(self):
-        return dict(Organisation.TYPES).get(self.organisation_type)
+        return Organisation.TYPE_LABELS.get(self.organisation_type)
 
     @cached_property
     def inbound_number(self):

app/utils/branding.py

@@ -1,6 +1,5 @@
 from app.models.organisation import Organisation
 
-NHS_TYPES = dict(Organisation.NHS_TYPES).keys()
 NHS_EMAIL_BRANDING_ID = 'a7dc4e56-660b-4db7-8cff-12c37b12b5ea'
 
 
@@ -23,14 +22,14 @@ def get_email_choices(service):
         yield ('govuk_and_org', f'GOV.UK and {service.organisation.name}')
 
     if (
-        service.organisation_type in NHS_TYPES
+        service.organisation_type in Organisation.NHS_TYPES
         and service.email_branding_id != NHS_EMAIL_BRANDING_ID
     ):
         yield ('nhs', 'NHS')
 
     if (
         service.organisation
-        and service.organisation_type not in NHS_TYPES
+        and service.organisation_type not in Organisation.NHS_TYPES
         and (
             service.email_branding_id is None  # GOV.UK is current branding
             or service.email_branding_id != organisation_branding_id
@@ -43,14 +42,14 @@ def get_letter_choices(service):
     organisation_branding_id = service.organisation.letter_branding_id if service.organisation else None
 
     if (
-        service.organisation_type in NHS_TYPES
+        service.organisation_type in Organisation.NHS_TYPES
         and service.letter_branding_name != 'NHS'
     ):
         yield ('nhs', 'NHS')
 
     if (
         service.organisation
-        and service.organisation_type not in NHS_TYPES
+        and service.organisation_type not in Organisation.NHS_TYPES
         and (
             service.letter_branding_id is None  # GOV.UK is current branding
             or service.letter_branding_id != organisation_branding_id