# Source code for fontTools.feaLib.error

    class FeatureLibError(Exception):
        def __init__(self, message, location=None):
            Exception.__init__(self, message)
            self.location = location

        def __str__(self):
            message = Exception.__str__(self)
            if self.location:
                return f"{self.location}: {message}"
            else:
                return message

    class IncludedFeaNotFound(FeatureLibError):
        def __str__(self):
            assert self.location is not None

            message = (
                "The following feature file should be included but cannot be found: "
                f"{Exception.__str__(self)}"
            )
            return f"{self.location}: {message}"