specify LLM for query

lightrag/base.py

@@ -10,6 +10,7 @@ from typing import (
     Literal,
     TypedDict,
     TypeVar,
+    Callable,
 )
 import numpy as np
 from .utils import EmbeddingFunc
@@ -83,6 +84,12 @@ class QueryParam:
 
     ids: list[str] | None = None
     """List of ids to filter the results."""
+    
+    model_func: Callable[..., object] | None = None
+    """Optional override for the LLM model function to use for this specific query.
+    If provided, this will be used instead of the global model function.
+    This allows using different models for different query modes.
+    """
 
 
 @dataclass