langchain/chains/llm.py/LLMChain/predict
class LLMChain:    def predict(self, callbacks: Callbacks = None, **kwargs: Any) -> str:
        """Format prompt with kwargs and pass to LLM.

        Args:
            callbacks: Callbacks to pass to LLMChain
            **kwargs: Keys to pass to prompt template.

        Returns:
            Completion from LLM.

        Example:
            .. code-block:: python

                completion = llm.predict(adjective="funny")
        """
        return self(kwargs, callbacks=callbacks)[self.output_key]