experimental[major]: upgrade pydantic (#26228)

libs/experimental/langchain_experimental/llm_symbolic_math/base.py

@@ -13,6 +13,7 @@ from langchain_core.callbacks.manager import (
     CallbackManagerForChainRun,
 )
 from langchain_core.prompts.base import BasePromptTemplate
+from pydantic import ConfigDict
 
 from langchain_experimental.llm_symbolic_math.prompt import PROMPT
 
@@ -36,9 +37,10 @@ class LLMSymbolicMathChain(Chain):
     input_key: str = "question"  #: :meta private:
     output_key: str = "answer"  #: :meta private:
 
-    class Config:
-        arbitrary_types_allowed = True
-        extra = "forbid"
+    model_config = ConfigDict(
+        arbitrary_types_allowed=True,
+        extra="forbid",
+    )
 
     @property
     def input_keys(self) -> List[str]: