We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
CSV export fails on converting uuid to json
Problematic JSON structure in https://grand-challenge.org/api/v1/cases/images/redacted_uuid/?format=csv

```
{"pk":"redacted_uuid","name":"redacted.png","study":null,"files":[{"pk":"redacted_uuid","image":"redacted_uuid","file":"https://grand-challenge.org/media/images/...mhd","image_type":"MHD"},{"pk":"redacted_uuid","image":"09b3b3d6-0994-43d2-b6a9-eaff634b8805","file":"https://grand-challenge.org/media/images/...zraw","image_type":"MHD"}],"reader_study_set":["https://grand-challenge.org/api/v1/reader-studies/redacted_uuid/","https://grand-challenge.org/api/v1/reader-studies/redacted_uuid/"],"archive_set":[],"job_set":[],"width":596,"height":596,"depth":null,"color_space":"RGB","modality":null,"eye_choice":"NA","stereoscopic_choice":null,"field_of_view":null,"shape_without_color":[596,596],"shape":[596,596,3],"voxel_width_mm":null,"voxel_height_mm":null,"voxel_depth_mm":null,"api_url":"https://grand-challenge.org/api/v1/cases/images/redacted_uuid/"}
```

Probably due to trying to serialize the list of files to json in https://github.com/comic/grand-challenge.org/blob/14bc3dd4002756e9cf4a32bb0f238859a9175252/app/grandchallenge/core/renderers.py#L26-L27

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `app/grandchallenge/core/renderers.py`
Content:
```
1 import json
2 
3 from rest_framework_csv.renderers import CSVRenderer
4 
5 
6 class PaginatedCSVRenderer(CSVRenderer):
7     results_field = "results"
8 
9     def render(self, data, *args, **kwargs):
10         if self.results_field in data:
11             data = data[self.results_field]
12 
13         return super().render(data, *args, **kwargs)
14 
15     def flatten_data(self, data):
16         """
17         Create a dictionary that is 1 level deep, with nested values serialized
18         as json. This means that the header rows are now consistent.
19         """
20         for row in data:
21             flat_row = {k: self._flatten_value(v) for k, v in row.items()}
22             yield flat_row
23 
24     @staticmethod
25     def _flatten_value(value):
26         if isinstance(value, (dict, list)):
27             return json.dumps(value)
28         else:
29             return value
30
```
--- 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/app/grandchallenge/core/renderers.py b/app/grandchallenge/core/renderers.py
--- a/app/grandchallenge/core/renderers.py
+++ b/app/grandchallenge/core/renderers.py
@@ -1,5 +1,7 @@
 import json
 
+from rest_framework.settings import api_settings
+from rest_framework.utils.encoders import JSONEncoder
 from rest_framework_csv.renderers import CSVRenderer
 
 
@@ -24,6 +26,11 @@
     @staticmethod
     def _flatten_value(value):
         if isinstance(value, (dict, list)):
-            return json.dumps(value)
+            return json.dumps(
+                value,
+                cls=JSONEncoder,
+                ensure_ascii=not api_settings.UNICODE_JSON,
+                allow_nan=not api_settings.STRICT_JSON,
+            )
         else:
             return value

{"golden_diff": "diff --git a/app/grandchallenge/core/renderers.py b/app/grandchallenge/core/renderers.py\n--- a/app/grandchallenge/core/renderers.py\n+++ b/app/grandchallenge/core/renderers.py\n@@ -1,5 +1,7 @@\n import json\n \n+from rest_framework.settings import api_settings\n+from rest_framework.utils.encoders import JSONEncoder\n from rest_framework_csv.renderers import CSVRenderer\n \n \n@@ -24,6 +26,11 @@\n     @staticmethod\n     def _flatten_value(value):\n         if isinstance(value, (dict, list)):\n-            return json.dumps(value)\n+            return json.dumps(\n+                value,\n+                cls=JSONEncoder,\n+                ensure_ascii=not api_settings.UNICODE_JSON,\n+                allow_nan=not api_settings.STRICT_JSON,\n+            )\n         else:\n             return value\n", "issue": "CSV export fails on converting uuid to json\nProblematic JSON structure in https://grand-challenge.org/api/v1/cases/images/redacted_uuid/?format=csv\r\n\r\n```\r\n{\"pk\":\"redacted_uuid\",\"name\":\"redacted.png\",\"study\":null,\"files\":[{\"pk\":\"redacted_uuid\",\"image\":\"redacted_uuid\",\"file\":\"https://grand-challenge.org/media/images/...mhd\",\"image_type\":\"MHD\"},{\"pk\":\"redacted_uuid\",\"image\":\"09b3b3d6-0994-43d2-b6a9-eaff634b8805\",\"file\":\"https://grand-challenge.org/media/images/...zraw\",\"image_type\":\"MHD\"}],\"reader_study_set\":[\"https://grand-challenge.org/api/v1/reader-studies/redacted_uuid/\",\"https://grand-challenge.org/api/v1/reader-studies/redacted_uuid/\"],\"archive_set\":[],\"job_set\":[],\"width\":596,\"height\":596,\"depth\":null,\"color_space\":\"RGB\",\"modality\":null,\"eye_choice\":\"NA\",\"stereoscopic_choice\":null,\"field_of_view\":null,\"shape_without_color\":[596,596],\"shape\":[596,596,3],\"voxel_width_mm\":null,\"voxel_height_mm\":null,\"voxel_depth_mm\":null,\"api_url\":\"https://grand-challenge.org/api/v1/cases/images/redacted_uuid/\"}\r\n```\r\n\r\nProbably due to trying to serialize the list of files to json in https://github.com/comic/grand-challenge.org/blob/14bc3dd4002756e9cf4a32bb0f238859a9175252/app/grandchallenge/core/renderers.py#L26-L27\n", "before_files": [{"content": "import json\n\nfrom rest_framework_csv.renderers import CSVRenderer\n\n\nclass PaginatedCSVRenderer(CSVRenderer):\n    results_field = \"results\"\n\n    def render(self, data, *args, **kwargs):\n        if self.results_field in data:\n            data = data[self.results_field]\n\n        return super().render(data, *args, **kwargs)\n\n    def flatten_data(self, data):\n        \"\"\"\n        Create a dictionary that is 1 level deep, with nested values serialized\n        as json. This means that the header rows are now consistent.\n        \"\"\"\n        for row in data:\n            flat_row = {k: self._flatten_value(v) for k, v in row.items()}\n            yield flat_row\n\n    @staticmethod\n    def _flatten_value(value):\n        if isinstance(value, (dict, list)):\n            return json.dumps(value)\n        else:\n            return value\n", "path": "app/grandchallenge/core/renderers.py"}], "after_files": [{"content": "import json\n\nfrom rest_framework.settings import api_settings\nfrom rest_framework.utils.encoders import JSONEncoder\nfrom rest_framework_csv.renderers import CSVRenderer\n\n\nclass PaginatedCSVRenderer(CSVRenderer):\n    results_field = \"results\"\n\n    def render(self, data, *args, **kwargs):\n        if self.results_field in data:\n            data = data[self.results_field]\n\n        return super().render(data, *args, **kwargs)\n\n    def flatten_data(self, data):\n        \"\"\"\n        Create a dictionary that is 1 level deep, with nested values serialized\n        as json. This means that the header rows are now consistent.\n        \"\"\"\n        for row in data:\n            flat_row = {k: self._flatten_value(v) for k, v in row.items()}\n            yield flat_row\n\n    @staticmethod\n    def _flatten_value(value):\n        if isinstance(value, (dict, list)):\n            return json.dumps(\n                value,\n                cls=JSONEncoder,\n                ensure_ascii=not api_settings.UNICODE_JSON,\n                allow_nan=not api_settings.STRICT_JSON,\n            )\n        else:\n            return value\n", "path": "app/grandchallenge/core/renderers.py"}]}