multiple: pydantic 2 compatibility, v0.3 (#26443)

Signed-off-by: ChengZi <chen.zhang@zilliz.com>
Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>
Co-authored-by: Bagatur <22008038+baskaryan@users.noreply.github.com>
Co-authored-by: Dan O'Donovan <dan.odonovan@gmail.com>
Co-authored-by: Tom Daniel Grande <tomdgrande@gmail.com>
Co-authored-by: Grande <Tom.Daniel.Grande@statsbygg.no>
Co-authored-by: Bagatur <baskaryan@gmail.com>
Co-authored-by: ccurme <chester.curme@gmail.com>
Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>
Co-authored-by: Tomaz Bratanic <bratanic.tomaz@gmail.com>
Co-authored-by: ZhangShenao <15201440436@163.com>
Co-authored-by: Friso H. Kingma <fhkingma@gmail.com>
Co-authored-by: ChengZi <chen.zhang@zilliz.com>
Co-authored-by: Nuno Campos <nuno@langchain.dev>
Co-authored-by: Morgante Pell <morgantep@google.com>

libs/community/langchain_community/llms/huggingface_hub.py

@@ -5,6 +5,7 @@ from langchain_core._api.deprecation import deprecated
 from langchain_core.callbacks import CallbackManagerForLLMRun
 from langchain_core.language_models.llms import LLM
 from langchain_core.utils import get_from_dict_or_env, pre_init
+from pydantic import ConfigDict
 
 from langchain_community.llms.utils import enforce_stop_tokens
 
@@ -42,7 +43,7 @@ class HuggingFaceHub(LLM):
             hf = HuggingFaceHub(repo_id="gpt2", huggingfacehub_api_token="my-api-key")
     """
 
-    client: Any  #: :meta private:
+    client: Any = None  #: :meta private:
     repo_id: Optional[str] = None
     """Model name to use. 
     If not provided, the default model for the chosen task will be used."""
@@ -55,8 +56,9 @@ class HuggingFaceHub(LLM):
 
     huggingfacehub_api_token: Optional[str] = None
 
-    class Config:
-        extra = "forbid"
+    model_config = ConfigDict(
+        extra="forbid",
+    )
 
     @pre_init
     def validate_environment(cls, values: Dict) -> Dict: