def __init__(
        self,
        *args: Any,
        description: str = "Lightning Trainer command line tool",
        env_prefix: str = "PL",
        default_env: bool = False,
        **kwargs: Any,
    ) -> None:
        """Initialize argument parser that supports configuration file input.

        For full details of accepted arguments see `ArgumentParser.__init__
        <https://jsonargparse.readthedocs.io/en/stable/#jsonargparse.ArgumentParser.__init__>`_.

        Args:
            description: Description of the tool shown when running ``--help``.
            env_prefix: Prefix for environment variables. Set ``default_env=True`` to enable env parsing.
            default_env: Whether to parse environment variables.

        """
        if not _JSONARGPARSE_SIGNATURES_AVAILABLE:
            raise ModuleNotFoundError(f"{_JSONARGPARSE_SIGNATURES_AVAILABLE}")
        super().__init__(*args, description=description, env_prefix=env_prefix, default_env=default_env, **kwargs)
        self.callback_keys: list[str] = []
        # separate optimizers and lr schedulers to know which were added
        self._optimizers: dict[str, tuple[Union[type, tuple[type, ...]], str]] = {}
        self._lr_schedulers: dict[str, tuple[Union[type, tuple[type, ...]], str]] = {}
Initialize argument parser that supports configuration file input.

        For full details of accepted arguments see `ArgumentParser.__init__
        <https://jsonargparse.readthedocs.io/en/stable/#jsonargparse.ArgumentParser.__init__>`_.

        Args:
            description: Description of the tool shown when running ``--help``.
            env_prefix: Prefix for environment variables. Set ``default_env=True`` to enable env parsing.
            default_env: Whether to parse environment variables.

        
src/lightning/pytorch/cli.py