Load options from a YAML-formated file.

        :param str filename: File from which to load the options.

        :raise:
            :IOError: If ``filename`` does not exist.

def set_options_from_JSON(self, filename):
        """Load options from a YAML-formated file.

        :param str filename: File from which to load the options.

        :raise:
            :IOError: If ``filename`` does not exist.
        """
        if not os.path.isfile(filename):
            raise IOError("File {0} not found".format(filename))
        data_str = "".join([x.strip() for x in open(filename).readlines()])
        data_dict = json.loads(data_str)
        self.set_options_from_dict(data_dict, filename)