style(anthropic): fix black formatting in normalize_system_role diff

Pure formatting changes to satisfy the lint gate:
- common_utils.py: collapse one-line dict literal
- handler.py: collapse one-line function-call assignment
- test_normalize_system_role.py: reformat multiline assertions,
  add blank line after nested import, fix missing trailing newline

No logic changes. All 13 normalize_system_role tests still pass.

litellm/llms/anthropic/common_utils.py

@@ -1033,9 +1033,7 @@ def normalize_system_role_in_anthropic_messages(
             elif content is not None and not isinstance(content, str):
                 # Best-effort: stringify unknown content shapes so callers
                 # don't silently lose information.
-                promoted_blocks.append(
-                    {"type": "text", "text": str(content)}
-                )
+                promoted_blocks.append({"type": "text", "text": str(content)})
         else:
             kept.append(m)
 

litellm/llms/anthropic/experimental_pass_through/messages/handler.py

@@ -411,9 +411,7 @@ def anthropic_messages_handler(
         # role."  OpenAI-style clients routinely send the system prompt as
         # messages[0]; lift those up to the top-level `system` parameter so
         # sync callers (litellm.messages.create) stay valid too. See #30705.
-        messages, system = normalize_system_role_in_anthropic_messages(
-            messages, system
-        )
+        messages, system = normalize_system_role_in_anthropic_messages(messages, system)
 
     metadata = validate_anthropic_api_metadata(metadata)
 

tests/test_litellm/llms/anthropic/test_normalize_system_role.py

@@ -40,9 +40,7 @@ class TestNormalizeSystemRole:
         new_messages, new_system = normalize_system_role_in_anthropic_messages(
             messages, system=None
         )
-        assert new_system == [
-            {"type": "text", "text": "you are a helpful assistant"}
-        ]
+        assert new_system == [{"type": "text", "text": "you are a helpful assistant"}]
         assert new_messages == [{"role": "user", "content": "hi"}]
 
     def test_promotes_content_block_system_message(self):
@@ -221,6 +219,7 @@ class TestSyncPathNormalization:
             from litellm.llms.anthropic.common_utils import (
                 normalize_system_role_in_anthropic_messages as real_normalize,
             )
+
             return real_normalize(messages, system)
 
         # Patch the symbol the handler imported.
@@ -242,9 +241,9 @@ class TestSyncPathNormalization:
         finally:
             handler_module.normalize_system_role_in_anthropic_messages = original
 
-        assert len(calls) >= 1, (
-            "sync handler did not invoke normalize_system_role_in_anthropic_messages"
-        )
+        assert (
+            len(calls) >= 1
+        ), "sync handler did not invoke normalize_system_role_in_anthropic_messages"
 
     def test_sync_handler_skips_normalizer_when_presanitized_flag_set(self):
         """
@@ -260,11 +259,14 @@ class TestSyncPathNormalization:
 
         calls = []
 
-        def spy_normalize(messages, system=None):  # pragma: no cover - patched at runtime
+        def spy_normalize(
+            messages, system=None
+        ):  # pragma: no cover - patched at runtime
             calls.append((list(messages), system))
             from litellm.llms.anthropic.common_utils import (
                 normalize_system_role_in_anthropic_messages as real_normalize,
             )
+
             return real_normalize(messages, system)
 
         original = handler_module.normalize_system_role_in_anthropic_messages
@@ -288,4 +290,4 @@ class TestSyncPathNormalization:
 
 
 if __name__ == "__main__":
-    sys.exit(pytest.main([__file__, "-v"]))
+    sys.exit(pytest.main([__file__, "-v"]))