Ensures that the path represents an existing file

        @type path: str
        @param path: path to check

def assert_valid_path(self, path):
        """
        Ensures that the path represents an existing file

        @type path: str
        @param path: path to check

        """
        if not isinstance(path, str):
            raise NotFoundResourceException(
                "Resource passed to load() method must be a file path")

        if not os.path.isfile(path):
            raise NotFoundResourceException(
                'File "{0}" does not exist'.format(path))