We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
add "gesamtstädtisch" as null-option to projects


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `meinberlin/apps/projects/admin.py`
Content:
```
1 from django.contrib import admin
2 from django.utils.translation import ugettext_lazy as _
3 
4 from adhocracy4.projects import models
5 
6 
7 class ProjectAdmin(admin.ModelAdmin):
8     list_display = (
9         '__str__', 'organisation', 'is_draft', 'is_archived', 'created'
10     )
11     list_filter = ('is_draft', 'is_archived', 'organisation')
12     search_fields = ('name',)
13     raw_id_fields = ('moderators', 'participants')
14     date_hierarchy = 'created'
15 
16     fieldsets = (
17         (None, {
18             'fields': ('name', 'organisation')
19         }),
20         (_('Topic and location'), {
21             'fields': ('topic', 'point', 'administrative_district'),
22         }),
23         (_('Information and result'), {
24             'fields': ('description', 'information', 'result'),
25         }),
26         (_('Settings'), {
27             'classes': ('collapse',),
28             'fields': ('is_public', 'is_draft', 'is_archived',
29                        'moderators', 'participants')
30         }),
31         (_('Images'), {
32             'classes': ('collapse',),
33             'fields': ('image', 'image_copyright', 'tile_image',
34                        'tile_image_copyright')
35         }),
36         (_('Contact'), {
37             'classes': ('collapse',),
38             'fields': ('contact_name', 'contact_address_text',
39                        'contact_phone', 'contact_email', 'contact_url'),
40         }),
41     )
42 
43 
44 # Overwrite adhocracy4.projects.admin
45 admin.site.unregister(models.Project)
46 admin.site.register(models.Project, ProjectAdmin)
47
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/meinberlin/apps/projects/admin.py b/meinberlin/apps/projects/admin.py
--- a/meinberlin/apps/projects/admin.py
+++ b/meinberlin/apps/projects/admin.py
@@ -40,6 +40,11 @@
         }),
     )
 
+    def formfield_for_foreignkey(self, db_field, request, **kwargs):
+        if db_field.name == 'administrative_district':
+            kwargs['empty_label'] = _('City wide')
+        return super().formfield_for_foreignkey(db_field, request, **kwargs)
+
 
 # Overwrite adhocracy4.projects.admin
 admin.site.unregister(models.Project)

{"golden_diff": "diff --git a/meinberlin/apps/projects/admin.py b/meinberlin/apps/projects/admin.py\n--- a/meinberlin/apps/projects/admin.py\n+++ b/meinberlin/apps/projects/admin.py\n@@ -40,6 +40,11 @@\n         }),\n     )\n \n+    def formfield_for_foreignkey(self, db_field, request, **kwargs):\n+        if db_field.name == 'administrative_district':\n+            kwargs['empty_label'] = _('City wide')\n+        return super().formfield_for_foreignkey(db_field, request, **kwargs)\n+\n \n # Overwrite adhocracy4.projects.admin\n admin.site.unregister(models.Project)\n", "issue": "add \"gesamtst\u00e4dtisch\" as null-option to projects\n\n", "before_files": [{"content": "from django.contrib import admin\nfrom django.utils.translation import ugettext_lazy as _\n\nfrom adhocracy4.projects import models\n\n\nclass ProjectAdmin(admin.ModelAdmin):\n    list_display = (\n        '__str__', 'organisation', 'is_draft', 'is_archived', 'created'\n    )\n    list_filter = ('is_draft', 'is_archived', 'organisation')\n    search_fields = ('name',)\n    raw_id_fields = ('moderators', 'participants')\n    date_hierarchy = 'created'\n\n    fieldsets = (\n        (None, {\n            'fields': ('name', 'organisation')\n        }),\n        (_('Topic and location'), {\n            'fields': ('topic', 'point', 'administrative_district'),\n        }),\n        (_('Information and result'), {\n            'fields': ('description', 'information', 'result'),\n        }),\n        (_('Settings'), {\n            'classes': ('collapse',),\n            'fields': ('is_public', 'is_draft', 'is_archived',\n                       'moderators', 'participants')\n        }),\n        (_('Images'), {\n            'classes': ('collapse',),\n            'fields': ('image', 'image_copyright', 'tile_image',\n                       'tile_image_copyright')\n        }),\n        (_('Contact'), {\n            'classes': ('collapse',),\n            'fields': ('contact_name', 'contact_address_text',\n                       'contact_phone', 'contact_email', 'contact_url'),\n        }),\n    )\n\n\n# Overwrite adhocracy4.projects.admin\nadmin.site.unregister(models.Project)\nadmin.site.register(models.Project, ProjectAdmin)\n", "path": "meinberlin/apps/projects/admin.py"}], "after_files": [{"content": "from django.contrib import admin\nfrom django.utils.translation import ugettext_lazy as _\n\nfrom adhocracy4.projects import models\n\n\nclass ProjectAdmin(admin.ModelAdmin):\n    list_display = (\n        '__str__', 'organisation', 'is_draft', 'is_archived', 'created'\n    )\n    list_filter = ('is_draft', 'is_archived', 'organisation')\n    search_fields = ('name',)\n    raw_id_fields = ('moderators', 'participants')\n    date_hierarchy = 'created'\n\n    fieldsets = (\n        (None, {\n            'fields': ('name', 'organisation')\n        }),\n        (_('Topic and location'), {\n            'fields': ('topic', 'point', 'administrative_district'),\n        }),\n        (_('Information and result'), {\n            'fields': ('description', 'information', 'result'),\n        }),\n        (_('Settings'), {\n            'classes': ('collapse',),\n            'fields': ('is_public', 'is_draft', 'is_archived',\n                       'moderators', 'participants')\n        }),\n        (_('Images'), {\n            'classes': ('collapse',),\n            'fields': ('image', 'image_copyright', 'tile_image',\n                       'tile_image_copyright')\n        }),\n        (_('Contact'), {\n            'classes': ('collapse',),\n            'fields': ('contact_name', 'contact_address_text',\n                       'contact_phone', 'contact_email', 'contact_url'),\n        }),\n    )\n\n    def formfield_for_foreignkey(self, db_field, request, **kwargs):\n        if db_field.name == 'administrative_district':\n            kwargs['empty_label'] = _('City wide')\n        return super().formfield_for_foreignkey(db_field, request, **kwargs)\n\n\n# Overwrite adhocracy4.projects.admin\nadmin.site.unregister(models.Project)\nadmin.site.register(models.Project, ProjectAdmin)\n", "path": "meinberlin/apps/projects/admin.py"}]}