def create_index_if_missing(self, index, settings=None):
try:<EOL><INDENT>return self.create_index(index, settings)<EOL><DEDENT>except IndexAlreadyExistsException as e:<EOL><INDENT>return e.result<EOL><DEDENT>
Creates an index if it doesn't already exist.

        If supplied, settings must be a dictionary.

        :param index: the name of the index
        :keyword settings: a settings object or a dict containing settings