We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
sposób widzenia załączników do nas wysłanych
Nie wiem czemu jest tak, że ja wchodzę w korespondencję z daną gminą w danym monitoringu, to przy mailach widzę załączniki:

![image](https://user-images.githubusercontent.com/36925935/37775670-d1d18a68-2de3-11e8-9787-af1c19084734.png)

A jak już wejdę z konkretną wiadomość, to ich nie ma:

![image](https://user-images.githubusercontent.com/36925935/37775701-ea66de2a-2de3-11e8-931c-cf61c2e5c964.png)

Czy to się da zmienić, żeby po wejściu z konkretną wiadomość też było widać te załączniki?

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `feder/letters/factories.py`
Content:
```
1 from email.mime.text import MIMEText
2 
3 import factory
4 import factory.fuzzy
5 from django.core.mail import EmailMessage
6 from factory.django import FileField
7 
8 from feder.cases.factories import CaseFactory
9 from feder.institutions.factories import InstitutionFactory
10 from feder.records.factories import RecordFactory
11 from feder.users.factories import UserFactory
12 from .models import Letter
13 
14 
15 class MailField(FileField):
16     DEFAULT_FILENAME = 'data.eml'
17 
18     def _make_data(self, params):
19         msg = MIMEText("Lorem ipsum")
20         msg['Subject'] = "Example message"
21         msg['From'] = "sender@example.com"
22         msg['To'] = "recipient@example.com"
23 
24         return params.get('data', msg.as_string().encode('utf-8'))
25 
26 
27 class LetterFactory(factory.django.DjangoModelFactory):
28     record = factory.SubFactory(RecordFactory)
29     title = factory.Sequence('title-letter-{0}'.format)
30     body = factory.Sequence('body-{0}'.format)
31     quote = factory.Sequence('quote-{0}'.format)
32 
33     class Meta:
34         model = Letter
35 
36 
37 class IncomingLetterFactory(LetterFactory):
38     author_institution = factory.SubFactory(InstitutionFactory)
39     email = factory.Sequence('xxx-{0}@example.com'.format)
40     note = factory.fuzzy.FuzzyText()
41     eml = MailField()
42 
43 
44 class OutgoingLetterFactory(LetterFactory):
45     author_user = factory.SubFactory(UserFactory)
46     is_draft = False
47     eml = MailField()
48 
49 
50 class DraftLetterFactory(OutgoingLetterFactory):
51     is_draft = True
52 
53 
54 class SendOutgoingLetterFactory(LetterFactory):
55     author_user = factory.SubFactory(UserFactory)
56 
57     is_send_yes = factory.PostGenerationMethodCall('send')
58
```
--- 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/feder/letters/factories.py b/feder/letters/factories.py
--- a/feder/letters/factories.py
+++ b/feder/letters/factories.py
@@ -1,15 +1,12 @@
 from email.mime.text import MIMEText
 
-import factory
 import factory.fuzzy
-from django.core.mail import EmailMessage
 from factory.django import FileField
 
-from feder.cases.factories import CaseFactory
 from feder.institutions.factories import InstitutionFactory
 from feder.records.factories import RecordFactory
 from feder.users.factories import UserFactory
-from .models import Letter
+from .models import Letter, Attachment
 
 
 class MailField(FileField):
@@ -55,3 +52,11 @@
     author_user = factory.SubFactory(UserFactory)
 
     is_send_yes = factory.PostGenerationMethodCall('send')
+
+
+class AttachmentFactory(factory.django.DjangoModelFactory):
+    letter = factory.SubFactory(InstitutionFactory)
+    attachment = factory.django.FileField()
+
+    class Meta:
+        model = Attachment

{"golden_diff": "diff --git a/feder/letters/factories.py b/feder/letters/factories.py\n--- a/feder/letters/factories.py\n+++ b/feder/letters/factories.py\n@@ -1,15 +1,12 @@\n from email.mime.text import MIMEText\n \n-import factory\n import factory.fuzzy\n-from django.core.mail import EmailMessage\n from factory.django import FileField\n \n-from feder.cases.factories import CaseFactory\n from feder.institutions.factories import InstitutionFactory\n from feder.records.factories import RecordFactory\n from feder.users.factories import UserFactory\n-from .models import Letter\n+from .models import Letter, Attachment\n \n \n class MailField(FileField):\n@@ -55,3 +52,11 @@\n     author_user = factory.SubFactory(UserFactory)\n \n     is_send_yes = factory.PostGenerationMethodCall('send')\n+\n+\n+class AttachmentFactory(factory.django.DjangoModelFactory):\n+    letter = factory.SubFactory(InstitutionFactory)\n+    attachment = factory.django.FileField()\n+\n+    class Meta:\n+        model = Attachment\n", "issue": "spos\u00f3b widzenia za\u0142\u0105cznik\u00f3w do nas wys\u0142anych\nNie wiem czemu jest tak, \u017ce ja wchodz\u0119 w korespondencj\u0119 z dan\u0105 gmin\u0105 w danym monitoringu, to przy mailach widz\u0119 za\u0142\u0105czniki:\r\n\r\n![image](https://user-images.githubusercontent.com/36925935/37775670-d1d18a68-2de3-11e8-9787-af1c19084734.png)\r\n\r\nA jak ju\u017c wejd\u0119 z konkretn\u0105 wiadomo\u015b\u0107, to ich nie ma:\r\n\r\n![image](https://user-images.githubusercontent.com/36925935/37775701-ea66de2a-2de3-11e8-931c-cf61c2e5c964.png)\r\n\r\nCzy to si\u0119 da zmieni\u0107, \u017ceby po wej\u015bciu z konkretn\u0105 wiadomo\u015b\u0107 te\u017c by\u0142o wida\u0107 te za\u0142\u0105czniki?\n", "before_files": [{"content": "from email.mime.text import MIMEText\n\nimport factory\nimport factory.fuzzy\nfrom django.core.mail import EmailMessage\nfrom factory.django import FileField\n\nfrom feder.cases.factories import CaseFactory\nfrom feder.institutions.factories import InstitutionFactory\nfrom feder.records.factories import RecordFactory\nfrom feder.users.factories import UserFactory\nfrom .models import Letter\n\n\nclass MailField(FileField):\n    DEFAULT_FILENAME = 'data.eml'\n\n    def _make_data(self, params):\n        msg = MIMEText(\"Lorem ipsum\")\n        msg['Subject'] = \"Example message\"\n        msg['From'] = \"sender@example.com\"\n        msg['To'] = \"recipient@example.com\"\n\n        return params.get('data', msg.as_string().encode('utf-8'))\n\n\nclass LetterFactory(factory.django.DjangoModelFactory):\n    record = factory.SubFactory(RecordFactory)\n    title = factory.Sequence('title-letter-{0}'.format)\n    body = factory.Sequence('body-{0}'.format)\n    quote = factory.Sequence('quote-{0}'.format)\n\n    class Meta:\n        model = Letter\n\n\nclass IncomingLetterFactory(LetterFactory):\n    author_institution = factory.SubFactory(InstitutionFactory)\n    email = factory.Sequence('xxx-{0}@example.com'.format)\n    note = factory.fuzzy.FuzzyText()\n    eml = MailField()\n\n\nclass OutgoingLetterFactory(LetterFactory):\n    author_user = factory.SubFactory(UserFactory)\n    is_draft = False\n    eml = MailField()\n\n\nclass DraftLetterFactory(OutgoingLetterFactory):\n    is_draft = True\n\n\nclass SendOutgoingLetterFactory(LetterFactory):\n    author_user = factory.SubFactory(UserFactory)\n\n    is_send_yes = factory.PostGenerationMethodCall('send')\n", "path": "feder/letters/factories.py"}], "after_files": [{"content": "from email.mime.text import MIMEText\n\nimport factory.fuzzy\nfrom factory.django import FileField\n\nfrom feder.institutions.factories import InstitutionFactory\nfrom feder.records.factories import RecordFactory\nfrom feder.users.factories import UserFactory\nfrom .models import Letter, Attachment\n\n\nclass MailField(FileField):\n    DEFAULT_FILENAME = 'data.eml'\n\n    def _make_data(self, params):\n        msg = MIMEText(\"Lorem ipsum\")\n        msg['Subject'] = \"Example message\"\n        msg['From'] = \"sender@example.com\"\n        msg['To'] = \"recipient@example.com\"\n\n        return params.get('data', msg.as_string().encode('utf-8'))\n\n\nclass LetterFactory(factory.django.DjangoModelFactory):\n    record = factory.SubFactory(RecordFactory)\n    title = factory.Sequence('title-letter-{0}'.format)\n    body = factory.Sequence('body-{0}'.format)\n    quote = factory.Sequence('quote-{0}'.format)\n\n    class Meta:\n        model = Letter\n\n\nclass IncomingLetterFactory(LetterFactory):\n    author_institution = factory.SubFactory(InstitutionFactory)\n    email = factory.Sequence('xxx-{0}@example.com'.format)\n    note = factory.fuzzy.FuzzyText()\n    eml = MailField()\n\n\nclass OutgoingLetterFactory(LetterFactory):\n    author_user = factory.SubFactory(UserFactory)\n    is_draft = False\n    eml = MailField()\n\n\nclass DraftLetterFactory(OutgoingLetterFactory):\n    is_draft = True\n\n\nclass SendOutgoingLetterFactory(LetterFactory):\n    author_user = factory.SubFactory(UserFactory)\n\n    is_send_yes = factory.PostGenerationMethodCall('send')\n\n\nclass AttachmentFactory(factory.django.DjangoModelFactory):\n    letter = factory.SubFactory(InstitutionFactory)\n    attachment = factory.django.FileField()\n\n    class Meta:\n        model = Attachment\n", "path": "feder/letters/factories.py"}]}