We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Add traits and variants support in l20nfile
L20n traits allow storing value variants and additional information for a unit. We need to add such support when parsing `.ftl` and convert resources.

```
file-menu =
    [xul/label]     File
    [xul/accesskey] F
```



--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `translate/storage/l20n.py`
Content:
```
1 # -*- coding: utf-8 -*-
2 #
3 # Copyright 2016 Zuza Software Foundation
4 #
5 # This file is part of translate.
6 #
7 # translate is free software; you can redistribute it and/or modify
8 # it under the terms of the GNU General Public License as published by
9 # the Free Software Foundation; either version 2 of the License, or
10 # (at your option) any later version.
11 #
12 # translate is distributed in the hope that it will be useful,
13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 # GNU General Public License for more details.
16 #
17 # You should have received a copy of the GNU General Public License
18 # along with this program; if not, see <http://www.gnu.org/licenses/>.
19 
20 from __future__ import absolute_import
21 
22 from codecs import iterencode
23 
24 from l20n.format.parser import FTLParser as L20nParser
25 from l20n.format.serializer import FTLSerializer as L20nSerializer
26 
27 from translate.storage import base
28 
29 
30 class l20nunit(base.TranslationUnit):
31     """Single L20n Entity"""
32 
33     def __init__(self, source='', id='', comment=''):
34         super(l20nunit, self).__init__(source)
35         self.id = id
36         self.value = source
37         self.comment = comment
38 
39     # Note that source and target are equivalent for monolingual units
40     def getsource(self):
41         return self.value
42 
43     def setsource(self, source):
44         self.value = source
45 
46     source = property(getsource, setsource)
47 
48     def gettarget(self):
49         return self.value
50 
51     def settarget(self, target):
52         self.value = target
53 
54     target = property(gettarget, settarget)
55 
56     def getid(self):
57         return self.id
58 
59     def setid(self, new_id):
60         self.id = new_id
61 
62     def getoutput(self):
63         return u"%s = %s\n" % (self.id, self.value)
64 
65 
66 class l20nfile(base.TranslationStore):
67     UnitClass = l20nunit
68     encoding = 'utf8'
69 
70     def __init__(self, inputfile=None):
71         super(l20nfile, self).__init__(unitclass=self.UnitClass)
72         self.filename = getattr(inputfile, 'name', '')
73         if inputfile is not None:
74             l20nsrc = inputfile.read()
75             self.parse(l20nsrc)
76             self.makeindex()
77 
78     def parse(self, l20nsrc):
79         text, encoding = self.detect_encoding(
80             l20nsrc, default_encodings=[self.encoding])
81         if not text:
82             raise IOError("Cannot detect encoding for %s." % (self.filename or
83                                                               "given string"))
84         l20nsrc = text
85 
86         parser = L20nParser()
87         ast, errors = parser.parseResource(l20nsrc)
88 
89         for entry in ast['body']:
90             if entry['type'] == 'Entity':
91                 translation = L20nSerializer().dumpPattern(entry['value'])
92                 comment = ''
93                 if entry['comment']:
94                     comment = entry['comment']['content']
95 
96                 newl20n = l20nunit(
97                     source=translation,
98                     id=entry['id']['name'],
99                     comment=comment
100                 )
101                 self.addunit(newl20n)
102 
103     def serialize(self, out):
104         """Write the units back to file."""
105         # Thanks to iterencode, a possible BOM is written only once
106         for chunk in iterencode((unit.getoutput() for unit in self.units), self.encoding):
107             out.write(chunk)
108
```
--- 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/translate/storage/l20n.py b/translate/storage/l20n.py
--- a/translate/storage/l20n.py
+++ b/translate/storage/l20n.py
@@ -27,6 +27,17 @@
 from translate.storage import base
 
 
+def dump_l20n_entity_value(entity):
+    serializer = L20nSerializer()
+    value = serializer.dumpPattern(entity['value'])
+
+    if len(entity['traits']):
+        traits = serializer.dumpMembers(entity['traits'], 2)
+        return u'{}\n{}'.format(value, traits)
+
+    return value
+
+
 class l20nunit(base.TranslationUnit):
     """Single L20n Entity"""
 
@@ -75,6 +86,19 @@
             self.parse(l20nsrc)
             self.makeindex()
 
+    def parse_entity(self, entity):
+        translation = dump_l20n_entity_value(entity)
+        comment = ''
+        if entity['comment']:
+            comment = entity['comment']['content']
+
+        newl20n = l20nunit(
+            source=translation,
+            id=entity['id']['name'],
+            comment=comment
+        )
+        self.addunit(newl20n)
+
     def parse(self, l20nsrc):
         text, encoding = self.detect_encoding(
             l20nsrc, default_encodings=[self.encoding])
@@ -88,17 +112,7 @@
 
         for entry in ast['body']:
             if entry['type'] == 'Entity':
-                translation = L20nSerializer().dumpPattern(entry['value'])
-                comment = ''
-                if entry['comment']:
-                    comment = entry['comment']['content']
-
-                newl20n = l20nunit(
-                    source=translation,
-                    id=entry['id']['name'],
-                    comment=comment
-                )
-                self.addunit(newl20n)
+                self.parse_entity(entry)
 
     def serialize(self, out):
         """Write the units back to file."""

{"golden_diff": "diff --git a/translate/storage/l20n.py b/translate/storage/l20n.py\n--- a/translate/storage/l20n.py\n+++ b/translate/storage/l20n.py\n@@ -27,6 +27,17 @@\n from translate.storage import base\n \n \n+def dump_l20n_entity_value(entity):\n+    serializer = L20nSerializer()\n+    value = serializer.dumpPattern(entity['value'])\n+\n+    if len(entity['traits']):\n+        traits = serializer.dumpMembers(entity['traits'], 2)\n+        return u'{}\\n{}'.format(value, traits)\n+\n+    return value\n+\n+\n class l20nunit(base.TranslationUnit):\n     \"\"\"Single L20n Entity\"\"\"\n \n@@ -75,6 +86,19 @@\n             self.parse(l20nsrc)\n             self.makeindex()\n \n+    def parse_entity(self, entity):\n+        translation = dump_l20n_entity_value(entity)\n+        comment = ''\n+        if entity['comment']:\n+            comment = entity['comment']['content']\n+\n+        newl20n = l20nunit(\n+            source=translation,\n+            id=entity['id']['name'],\n+            comment=comment\n+        )\n+        self.addunit(newl20n)\n+\n     def parse(self, l20nsrc):\n         text, encoding = self.detect_encoding(\n             l20nsrc, default_encodings=[self.encoding])\n@@ -88,17 +112,7 @@\n \n         for entry in ast['body']:\n             if entry['type'] == 'Entity':\n-                translation = L20nSerializer().dumpPattern(entry['value'])\n-                comment = ''\n-                if entry['comment']:\n-                    comment = entry['comment']['content']\n-\n-                newl20n = l20nunit(\n-                    source=translation,\n-                    id=entry['id']['name'],\n-                    comment=comment\n-                )\n-                self.addunit(newl20n)\n+                self.parse_entity(entry)\n \n     def serialize(self, out):\n         \"\"\"Write the units back to file.\"\"\"\n", "issue": "Add traits and variants support in l20nfile\nL20n traits allow storing value variants and additional information for a unit. We need to add such support when parsing `.ftl` and convert resources.\r\n\r\n```\r\nfile-menu =\r\n    [xul/label]     File\r\n    [xul/accesskey] F\r\n```\r\n\r\n\n", "before_files": [{"content": "# -*- coding: utf-8 -*-\n#\n# Copyright 2016 Zuza Software Foundation\n#\n# This file is part of translate.\n#\n# translate is free software; you can redistribute it and/or modify\n# it under the terms of the GNU General Public License as published by\n# the Free Software Foundation; either version 2 of the License, or\n# (at your option) any later version.\n#\n# translate is distributed in the hope that it will be useful,\n# but WITHOUT ANY WARRANTY; without even the implied warranty of\n# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n# GNU General Public License for more details.\n#\n# You should have received a copy of the GNU General Public License\n# along with this program; if not, see <http://www.gnu.org/licenses/>.\n\nfrom __future__ import absolute_import\n\nfrom codecs import iterencode\n\nfrom l20n.format.parser import FTLParser as L20nParser\nfrom l20n.format.serializer import FTLSerializer as L20nSerializer\n\nfrom translate.storage import base\n\n\nclass l20nunit(base.TranslationUnit):\n    \"\"\"Single L20n Entity\"\"\"\n\n    def __init__(self, source='', id='', comment=''):\n        super(l20nunit, self).__init__(source)\n        self.id = id\n        self.value = source\n        self.comment = comment\n\n    # Note that source and target are equivalent for monolingual units\n    def getsource(self):\n        return self.value\n\n    def setsource(self, source):\n        self.value = source\n\n    source = property(getsource, setsource)\n\n    def gettarget(self):\n        return self.value\n\n    def settarget(self, target):\n        self.value = target\n\n    target = property(gettarget, settarget)\n\n    def getid(self):\n        return self.id\n\n    def setid(self, new_id):\n        self.id = new_id\n\n    def getoutput(self):\n        return u\"%s = %s\\n\" % (self.id, self.value)\n\n\nclass l20nfile(base.TranslationStore):\n    UnitClass = l20nunit\n    encoding = 'utf8'\n\n    def __init__(self, inputfile=None):\n        super(l20nfile, self).__init__(unitclass=self.UnitClass)\n        self.filename = getattr(inputfile, 'name', '')\n        if inputfile is not None:\n            l20nsrc = inputfile.read()\n            self.parse(l20nsrc)\n            self.makeindex()\n\n    def parse(self, l20nsrc):\n        text, encoding = self.detect_encoding(\n            l20nsrc, default_encodings=[self.encoding])\n        if not text:\n            raise IOError(\"Cannot detect encoding for %s.\" % (self.filename or\n                                                              \"given string\"))\n        l20nsrc = text\n\n        parser = L20nParser()\n        ast, errors = parser.parseResource(l20nsrc)\n\n        for entry in ast['body']:\n            if entry['type'] == 'Entity':\n                translation = L20nSerializer().dumpPattern(entry['value'])\n                comment = ''\n                if entry['comment']:\n                    comment = entry['comment']['content']\n\n                newl20n = l20nunit(\n                    source=translation,\n                    id=entry['id']['name'],\n                    comment=comment\n                )\n                self.addunit(newl20n)\n\n    def serialize(self, out):\n        \"\"\"Write the units back to file.\"\"\"\n        # Thanks to iterencode, a possible BOM is written only once\n        for chunk in iterencode((unit.getoutput() for unit in self.units), self.encoding):\n            out.write(chunk)\n", "path": "translate/storage/l20n.py"}], "after_files": [{"content": "# -*- coding: utf-8 -*-\n#\n# Copyright 2016 Zuza Software Foundation\n#\n# This file is part of translate.\n#\n# translate is free software; you can redistribute it and/or modify\n# it under the terms of the GNU General Public License as published by\n# the Free Software Foundation; either version 2 of the License, or\n# (at your option) any later version.\n#\n# translate is distributed in the hope that it will be useful,\n# but WITHOUT ANY WARRANTY; without even the implied warranty of\n# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n# GNU General Public License for more details.\n#\n# You should have received a copy of the GNU General Public License\n# along with this program; if not, see <http://www.gnu.org/licenses/>.\n\nfrom __future__ import absolute_import\n\nfrom codecs import iterencode\n\nfrom l20n.format.parser import FTLParser as L20nParser\nfrom l20n.format.serializer import FTLSerializer as L20nSerializer\n\nfrom translate.storage import base\n\n\ndef dump_l20n_entity_value(entity):\n    serializer = L20nSerializer()\n    value = serializer.dumpPattern(entity['value'])\n\n    if len(entity['traits']):\n        traits = serializer.dumpMembers(entity['traits'], 2)\n        return u'{}\\n{}'.format(value, traits)\n\n    return value\n\n\nclass l20nunit(base.TranslationUnit):\n    \"\"\"Single L20n Entity\"\"\"\n\n    def __init__(self, source='', id='', comment=''):\n        super(l20nunit, self).__init__(source)\n        self.id = id\n        self.value = source\n        self.comment = comment\n\n    # Note that source and target are equivalent for monolingual units\n    def getsource(self):\n        return self.value\n\n    def setsource(self, source):\n        self.value = source\n\n    source = property(getsource, setsource)\n\n    def gettarget(self):\n        return self.value\n\n    def settarget(self, target):\n        self.value = target\n\n    target = property(gettarget, settarget)\n\n    def getid(self):\n        return self.id\n\n    def setid(self, new_id):\n        self.id = new_id\n\n    def getoutput(self):\n        return u\"%s = %s\\n\" % (self.id, self.value)\n\n\nclass l20nfile(base.TranslationStore):\n    UnitClass = l20nunit\n    encoding = 'utf8'\n\n    def __init__(self, inputfile=None):\n        super(l20nfile, self).__init__(unitclass=self.UnitClass)\n        self.filename = getattr(inputfile, 'name', '')\n        if inputfile is not None:\n            l20nsrc = inputfile.read()\n            self.parse(l20nsrc)\n            self.makeindex()\n\n    def parse_entity(self, entity):\n        translation = dump_l20n_entity_value(entity)\n        comment = ''\n        if entity['comment']:\n            comment = entity['comment']['content']\n\n        newl20n = l20nunit(\n            source=translation,\n            id=entity['id']['name'],\n            comment=comment\n        )\n        self.addunit(newl20n)\n\n    def parse(self, l20nsrc):\n        text, encoding = self.detect_encoding(\n            l20nsrc, default_encodings=[self.encoding])\n        if not text:\n            raise IOError(\"Cannot detect encoding for %s.\" % (self.filename or\n                                                              \"given string\"))\n        l20nsrc = text\n\n        parser = L20nParser()\n        ast, errors = parser.parseResource(l20nsrc)\n\n        for entry in ast['body']:\n            if entry['type'] == 'Entity':\n                self.parse_entity(entry)\n\n    def serialize(self, out):\n        \"\"\"Write the units back to file.\"\"\"\n        # Thanks to iterencode, a possible BOM is written only once\n        for chunk in iterencode((unit.getoutput() for unit in self.units), self.encoding):\n            out.write(chunk)\n", "path": "translate/storage/l20n.py"}]}