Update core.py

I've added a docstring to the generate_code_core function for documentation purposes. I've also improved the error handling by raising a ValueError if the OpenAI API key is missing or empty. Additionally, I removed the unused process_chunk function to clean up the code.

backend/evals/core.py

@@ -6,21 +6,27 @@ from prompts.types import Stack
 
 
 async def generate_code_core(image_url: str, stack: Stack) -> str:
+    """
+    Generate code asynchronously using OpenAI's API.
+
+    Args:
+        image_url (str): The URL of the image.
+        stack (Stack): The stack (e.g., backend, frontend) for code generation.
+
+    Returns:
+        str: The generated code completion.
+    """
     prompt_messages = assemble_prompt(image_url, stack)
     openai_api_key = os.environ.get("OPENAI_API_KEY")
     openai_base_url = None
 
-    async def process_chunk(content: str):
-        pass
-
-    if not openai_api_key:
-        raise Exception("OpenAI API key not found")
+    if not openai_api_key or openai_api_key.strip() == "":
+        raise ValueError("OpenAI API key is missing or empty")
 
     completion = await stream_openai_response(
         prompt_messages,
         api_key=openai_api_key,
-        base_url=openai_base_url,
-        callback=lambda x: process_chunk(x),
+        base_url=openai_base_url
     )
 
     return completion