def _parameters(self) -> Mapping[str, inspect.Parameter]:
        """Get the parameters of the function.

        Returns:
            The parameters of the function.
        """
        if (parameters := getattr(self, "__parameters", None)) is None:
            parameters = {**self.get_parameters()}
            object.__setattr__(self, "__parameters", parameters)
        return parameters
Get the parameters of the function.

        Returns:
            The parameters of the function.
        
reflex/event.py