LangChain Reference home pageLangChain ReferenceLangChain Reference
  • GitHub
  • Main Docs
Deep Agents
LangChain
LangGraph
Integrations
LangSmith
  • Overview
    • Overview
    • Caches
    • Callbacks
    • Documents
    • Document loaders
    • Embeddings
    • Exceptions
    • Language models
    • Serialization
    • Output parsers
    • Prompts
    • Rate limiters
    • Retrievers
    • Runnables
    • Utilities
    • Vector stores
    MCP Adapters
    Standard Tests
    Text Splitters
    ⌘I

    LangChain Assistant

    Ask a question to get started

    Enter to send•Shift+Enter new line

    Menu

    OverviewCachesCallbacksDocumentsDocument loadersEmbeddingsExceptionsLanguage modelsSerializationOutput parsersPromptsRate limitersRetrieversRunnablesUtilitiesVector stores
    MCP Adapters
    Standard Tests
    Text Splitters
    Language
    Theme
    Pythonlangchain-coreutilspydanticpre_init
    Functionā—Since v0.2

    pre_init

    Copy
    pre_init(
        func: Callable[[Any, dict[str, Any]], Any],
    ) -> Callable
    View source on GitHub
    [
    [
    Any
    ,
    dict
    [
    str
    ,
    Any
    ]
    ]
    ,
    Any
    ]

    Parameters

    NameTypeDescription
    func*Callable[[Any, dict[str, Any]], Any]

    Decorator to run a function before model initialization.

    The function to run before model initialization.