Tweak type hints to match dependency's behavior. (#11355)

Needs #11353 to merge first, and a new `langchain` to be published with
those changes.

libs/experimental/langchain_experimental/sql/vector_sql.py

@@ -1,7 +1,7 @@
 """Vector SQL Database Chain Retriever"""
 from __future__ import annotations
 
-from typing import Any, Dict, List, Optional, Union
+from typing import Any, Dict, List, Optional, Sequence, Union
 
 from langchain.callbacks.manager import CallbackManagerForChainRun
 from langchain.chains.llm import LLMChain
@@ -76,10 +76,8 @@ class VectorSQLRetrieveAllOutputParser(VectorSQLOutputParser):
         return super().parse(text)
 
 
-def get_result_from_sqldb(
-    db: SQLDatabase, cmd: str
-) -> Union[str, List[Dict[str, Any]], Dict[str, Any]]:
-    result = db._execute(cmd, fetch="all")  # type: ignore
+def get_result_from_sqldb(db: SQLDatabase, cmd: str) -> Sequence[Dict[str, Any]]:
+    result = db._execute(cmd, fetch="all")
     return result
 
 
@@ -179,8 +177,9 @@ class VectorSQLDatabaseChain(SQLDatabaseChain):
             _run_manager.on_text("\nSQLResult: ", verbose=self.verbose)
             _run_manager.on_text(str(result), color="yellow", verbose=self.verbose)
             # If return direct, we just set the final result equal to
-            # the result of the sql query result, otherwise try to get a human readable
-            # final answer
+            # the result of the sql query result (`Sequence[Dict[str, Any]]`),
+            # otherwise try to get a human readable final answer (`str`).
+            final_result: Union[str, Sequence[Dict[str, Any]]]
             if self.return_direct:
                 final_result = result
             else: