Function validate_callback

dash/_validate.py:22–51

(outputs, inputs, state, extra_args, types)

def validate_callback(outputs, inputs, state, extra_args, types):
    Input, Output, State = types
    if extra_args:
        if not isinstance(extra_args[0], (Output, Input, State)):
            raise exceptions.IncorrectTypeException(
                dedent(
                    f"""
                    Callback arguments must be `Output`, `Input`, or `State` objects,
                    optionally wrapped in a list or tuple. We found (possibly after
                    unwrapping a list or tuple):
                    {repr(extra_args[0])}
                    """
                )
            )

        raise exceptions.IncorrectTypeException(
            dedent(
                f"""
                In a callback definition, you must provide all Outputs first,
                then all Inputs, then all States. After this item:
                {(outputs + inputs + state)[-1]!r}
                we found this item next:
                {extra_args[0]!r}
                """
            )
        )

    for args in [outputs, inputs, state]:
        for arg in args:
            validate_callback_arg(arg)


def validate_callback_arg(arg):