core[patch]: update LanguageModelInput from List to Sequence (#14405)

Co-authored-by: Erick Friis <erick@langchain.dev>

libs/core/langchain_core/language_models/base.py

@@ -48,7 +48,7 @@ def _get_token_ids_default_method(text: str) -> List[int]:
     return tokenizer.encode(text)
 
 
-LanguageModelInput = Union[PromptValue, str, List[BaseMessage]]
+LanguageModelInput = Union[PromptValue, str, Sequence[BaseMessage]]
 LanguageModelOutput = Union[BaseMessage, str]
 LanguageModelLike = Runnable[LanguageModelInput, LanguageModelOutput]
 LanguageModelOutputVar = TypeVar("LanguageModelOutputVar", BaseMessage, str)

libs/core/langchain_core/language_models/chat_models.py

@@ -142,7 +142,7 @@ class BaseChatModel(BaseLanguageModel[BaseMessage], ABC):
             return input
         elif isinstance(input, str):
             return StringPromptValue(text=input)
-        elif isinstance(input, list):
+        elif isinstance(input, Sequence):
             return ChatPromptValue(messages=input)
         else:
             raise ValueError(

libs/core/langchain_core/language_models/llms.py

@@ -205,7 +205,7 @@ class BaseLLM(BaseLanguageModel[str], ABC):
             return input
         elif isinstance(input, str):
             return StringPromptValue(text=input)
-        elif isinstance(input, list):
+        elif isinstance(input, Sequence):
             return ChatPromptValue(messages=input)
         else:
             raise ValueError(