How to use the mutmut.__init__.RelativeMutationID function in mutmut

def __init__(self, source=None, mutation_id=ALL, dict_synonyms=None, filename=None, config=None, index=0):
        self.index = index
        self.remove_newline_at_end = False
        self._source = None
        self._set_source(source)
        self.mutation_id = mutation_id
        self.performed_mutation_ids = []
        assert isinstance(mutation_id, RelativeMutationID)
        self.current_line_index = 0
        self.filename = filename
        self.stack = []
        self.dict_synonyms = (dict_synonyms or []) + ['dict']
        self._source_by_line_number = None
        self._pragma_no_mutate_lines = None
        self._path_by_line = None
        self.config = config
        self.skip = False

self.line = line
        self.index = index
        self.line_number = line_number
        self.filename = filename

    def __repr__(self):
        return 'MutationID(line="{}", index={}, line_number={}, filename={})'.format(self.line, self.index, self.line_number, self.filename)

    def __eq__(self, other):
        return (self.line, self.index, self.line_number) == (other.line, other.index, other.line_number)

    def __hash__(self):
        return hash((self.line, self.index, self.line_number))


ALL = RelativeMutationID(filename='%all%', line='%all%', index=-1, line_number=-1)


class InvalidASTPatternException(Exception):
    pass


class ASTPattern(object):
    def __init__(self, source, **definitions):
        if definitions is None:
            definitions = {}
        source = source.strip()

        self.definitions = definitions

        self.module = parse(source)

def mutation_id_of_current_index(self):
        return RelativeMutationID(filename=self.filename, line=self.current_source_line, index=self.index, line_number=self.current_line_index)