neo4j_rm support litellm embedding model (#1771)

Co-authored-by: xucai <[email protected]>

Author: xucailiang

dspy/retrieve/neo4j_rm.py

@@ -1,5 +1,5 @@
 import os
-from typing import Any, List, Optional, Union
+from typing import Any, List, Optional, Union, Callable
 
 import backoff
 from openai import (
@@ -108,6 +108,7 @@ def __init__(
         retrieval_query: str = None,
         embedding_provider: str = "openai",
         embedding_model: str = "text-embedding-ada-002",
+        embedding_function: Optional[Callable] = None,
     ):
         super().__init__(k=k)
         self.index_name = index_name
@@ -136,7 +137,7 @@ def __init__(
         ) as e:
             raise ConnectionError("Failed to connect to Neo4j database") from e
 
-        self.embedder = Embedder(provider=embedding_provider, model=embedding_model)
+        self.embedder = embedding_function or Embedder(provider=embedding_provider, model=embedding_model)
 
     def forward(self, query_or_queries: Union[str, List[str]], k: Optional[int]) -> Prediction:
         if not isinstance(query_or_queries, list):