We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Broken multiple interface notation in schema
### What I'm trying to achieve
To use Apollo tooling to generate TS types for the application queries. However, it fails because Saleor's schema uses comma as a separator instead of ampersand. More: https://github.com/apollographql/apollo-tooling/issues/434 

### Steps to reproduce the problem
1. Go to mirumee/saleor-dashboard repository and clone it
2. Copy schema from core to dashboard
3. `npm run build-types`
4. Notice that it fails at multiple interface implementation.

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `saleor/graphql/management/commands/get_graphql_schema.py`
Content:
```
1 from django.core.management.base import BaseCommand
2 from graphql import print_schema
3 
4 from ...api import schema
5 
6 
7 class Command(BaseCommand):
8     help = "Writes SDL for GraphQL API schema to stdout"
9 
10     def handle(self, *args, **options):
11         self.stdout.write(print_schema(schema))
12
```
--- 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/saleor/graphql/management/commands/get_graphql_schema.py b/saleor/graphql/management/commands/get_graphql_schema.py
--- a/saleor/graphql/management/commands/get_graphql_schema.py
+++ b/saleor/graphql/management/commands/get_graphql_schema.py
@@ -8,4 +8,14 @@
     help = "Writes SDL for GraphQL API schema to stdout"
 
     def handle(self, *args, **options):
-        self.stdout.write(print_schema(schema))
+        """Support multiple interface notation in schema for Apollo tooling.
+
+        In `graphql-core` V2 separator for interaces is `,`.
+        Apollo tooling to generate TypeScript types using `&` as interfaces separator.
+        https://github.com/graphql-python/graphql-core/pull/258
+        """
+        printed_schema = print_schema(schema)
+        for line in printed_schema.splitlines():
+            if "implements" in line:
+                line = line.replace(",", " &")
+            self.stdout.write(f"{line}\n")

{"golden_diff": "diff --git a/saleor/graphql/management/commands/get_graphql_schema.py b/saleor/graphql/management/commands/get_graphql_schema.py\n--- a/saleor/graphql/management/commands/get_graphql_schema.py\n+++ b/saleor/graphql/management/commands/get_graphql_schema.py\n@@ -8,4 +8,14 @@\n     help = \"Writes SDL for GraphQL API schema to stdout\"\n \n     def handle(self, *args, **options):\n-        self.stdout.write(print_schema(schema))\n+        \"\"\"Support multiple interface notation in schema for Apollo tooling.\n+\n+        In `graphql-core` V2 separator for interaces is `,`.\n+        Apollo tooling to generate TypeScript types using `&` as interfaces separator.\n+        https://github.com/graphql-python/graphql-core/pull/258\n+        \"\"\"\n+        printed_schema = print_schema(schema)\n+        for line in printed_schema.splitlines():\n+            if \"implements\" in line:\n+                line = line.replace(\",\", \" &\")\n+            self.stdout.write(f\"{line}\\n\")\n", "issue": "Broken multiple interface notation in schema\n### What I'm trying to achieve\r\nTo use Apollo tooling to generate TS types for the application queries. However, it fails because Saleor's schema uses comma as a separator instead of ampersand. More: https://github.com/apollographql/apollo-tooling/issues/434 \r\n\r\n### Steps to reproduce the problem\r\n1. Go to mirumee/saleor-dashboard repository and clone it\r\n2. Copy schema from core to dashboard\r\n3. `npm run build-types`\r\n4. Notice that it fails at multiple interface implementation.\n", "before_files": [{"content": "from django.core.management.base import BaseCommand\nfrom graphql import print_schema\n\nfrom ...api import schema\n\n\nclass Command(BaseCommand):\n    help = \"Writes SDL for GraphQL API schema to stdout\"\n\n    def handle(self, *args, **options):\n        self.stdout.write(print_schema(schema))\n", "path": "saleor/graphql/management/commands/get_graphql_schema.py"}], "after_files": [{"content": "from django.core.management.base import BaseCommand\nfrom graphql import print_schema\n\nfrom ...api import schema\n\n\nclass Command(BaseCommand):\n    help = \"Writes SDL for GraphQL API schema to stdout\"\n\n    def handle(self, *args, **options):\n        \"\"\"Support multiple interface notation in schema for Apollo tooling.\n\n        In `graphql-core` V2 separator for interaces is `,`.\n        Apollo tooling to generate TypeScript types using `&` as interfaces separator.\n        https://github.com/graphql-python/graphql-core/pull/258\n        \"\"\"\n        printed_schema = print_schema(schema)\n        for line in printed_schema.splitlines():\n            if \"implements\" in line:\n                line = line.replace(\",\", \" &\")\n            self.stdout.write(f\"{line}\\n\")\n", "path": "saleor/graphql/management/commands/get_graphql_schema.py"}]}