fix(factory.py): handle message content being a list instead of string

Fixes https://github.com/BerriAI/litellm/issues/4679

litellm/llms/prompt_templates/factory.py

@@ -2393,7 +2393,16 @@ def custom_prompt(
             if role in role_dict and "post_message" in role_dict[role]
             else ""
         )
-        prompt += pre_message_str + message["content"] + post_message_str
+        if isinstance(message["content"], str):
+            prompt += pre_message_str + message["content"] + post_message_str
+        elif isinstance(message["content"], list):
+            text_str = ""
+            for content in message["content"]:
+                if content.get("text", None) is not None and isinstance(
+                    content["text"], str
+                ):
+                    text_str += content["text"]
+            prompt += pre_message_str + text_str + post_message_str
 
         if role == "assistant":
             prompt += eos_token

litellm/tests/test_bedrock_completion.py

@@ -599,9 +599,19 @@ def test_bedrock_claude_3(image_url):
 
 
 @pytest.mark.parametrize(
-    "system", ["You are an AI", [{"type": "text", "text": "You are an AI"}]]
+    "system",
+    ["You are an AI", [{"type": "text", "text": "You are an AI"}]],
 )
-def test_bedrock_claude_3_system_prompt(system):
+@pytest.mark.parametrize(
+    "model",
+    [
+        "anthropic.claude-3-sonnet-20240229-v1:0",
+        "meta.llama3-70b-instruct-v1:0",
+        "anthropic.claude-v2",
+        "mistral.mixtral-8x7b-instruct-v0:1",
+    ],
+)
+def test_bedrock_system_prompt(system, model):
     try:
         litellm.set_verbose = True
         data = {
@@ -614,7 +624,7 @@ def test_bedrock_claude_3_system_prompt(system):
             ],
         }
         response: ModelResponse = completion(
-            model="bedrock/anthropic.claude-3-sonnet-20240229-v1:0",
+            model="bedrock/{}".format(model),
             **data,
         )  # type: ignore
         # Add any assertions here to check the response