fix: update method calls from dict to model_dump in Chain (#33035)

Author: mdrxy

libs/langchain/langchain/chains/base.py

@@ -750,11 +750,11 @@ def dict(self, **kwargs: Any) -> dict:
         Example:
             .. code-block:: python
 
-                chain.dict(exclude_unset=True)
+                chain.model_dump(exclude_unset=True)
                 # -> {"_type": "foo", "verbose": False, ...}
 
         """
-        _dict = super().dict(**kwargs)
+        _dict = super().model_dump(**kwargs)
         with contextlib.suppress(NotImplementedError):
             _dict["_type"] = self._chain_type
         return _dict
@@ -779,7 +779,7 @@ def save(self, file_path: Union[Path, str]) -> None:
             raise ValueError(msg)
 
         # Fetch dictionary to save
-        chain_dict = self.dict()
+        chain_dict = self.model_dump()
         if "_type" not in chain_dict:
             msg = f"Chain {self} does not support saving."
             raise NotImplementedError(msg)